diff mbox

[igt,v3,01/11] igt/perf: add i915 perf stream tests for Haswell

Message ID 20161109161602.2402-2-robert@sixbynine.org (mailing list archive)
State New, archived
Headers show

Commit Message

Robert Bragg Nov. 9, 2016, 4:15 p.m. UTC
Signed-off-by: Robert Bragg <robert@sixbynine.org>
---
 tests/Makefile.sources |    1 +
 tests/perf.c           | 2220 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 2221 insertions(+)
 create mode 100644 tests/perf.c

Comments

Chris Wilson Nov. 9, 2016, 4:33 p.m. UTC | #1
On Wed, Nov 09, 2016 at 04:15:52PM +0000, Robert Bragg wrote:
> +static void
> +test_i915_ref_count(void)
> +{
> +        int oa_exponent = 13; /* 1 millisecond */
> +        uint64_t properties[] = {
> +                /* Include OA reports in samples */
> +                DRM_I915_PERF_PROP_SAMPLE_OA, true,
> +
> +                /* OA unit configuration */
> +                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
> +                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
> +                DRM_I915_PERF_PROP_OA_EXPONENT, oa_exponent,
> +        };
> +        struct drm_i915_perf_open_param param = {
> +                .flags = I915_PERF_FLAG_FD_CLOEXEC,
> +                .num_properties = sizeof(properties) / 16,
> +                .properties_ptr = (uint64_t)properties,
> +        };
> +        unsigned baseline, ref_count0, ref_count1;
> +        int stream_fd;
> +        uint32_t oa_report0[64];
> +        uint32_t oa_report1[64];
> +
> +        close(drm_fd);
> +        baseline = read_i915_module_ref();
> +        igt_debug("baseline ref count (drm fd closed) = %u\n", baseline);
> +
> +        drm_fd = drm_open_driver_render(DRIVER_INTEL);

Write this as a standalone (or first before igt_fixture) test and use
__drm_open_driver() (or export __drm_open_driver_render() if you insist)
so that we know that the extra driver ref taken by igt is not fouling up
your results..

> +        ref_count0 = read_i915_module_ref();
> +        igt_debug("initial ref count with drm_fd open = %u\n", ref_count0);
> +        igt_assert(ref_count0 > baseline);
> +
> +        stream_fd = __perf_open(drm_fd, &param);
> +        ref_count1 = read_i915_module_ref();
> +        igt_debug("ref count after opening i915 perf stream = %u\n", ref_count1);
> +        igt_assert(ref_count1 > ref_count0);
> +
> +        close(drm_fd);
> +        ref_count0 = read_i915_module_ref();
> +        igt_debug("ref count after closing drm fd = %u\n", ref_count0);
> +
> +        igt_assert(ref_count0 > baseline);
> +
> +        read_2_oa_reports(stream_fd,
> +                          I915_OA_FORMAT_A45_B8_C8, 256,
> +                          oa_exponent,
> +                          oa_report0,
> +                          oa_report1,
> +                          false); /* not just timer reports */
> +
> +        close(stream_fd);
> +        ref_count0 = read_i915_module_ref();
> +        igt_debug("ref count after closing i915 perf stream fd = %u\n", ref_count0);
> +        igt_assert_eq(ref_count0, baseline);
> +
> +        drm_fd = drm_open_driver_render(DRIVER_INTEL);
> +}
Matthew Auld Nov. 10, 2016, 11:03 p.m. UTC | #2
On 11/09, Robert Bragg wrote:
> Signed-off-by: Robert Bragg <robert@sixbynine.org>
> ---
>  tests/Makefile.sources |    1 +
>  tests/perf.c           | 2220 ++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 2221 insertions(+)
>  create mode 100644 tests/perf.c
> 
> diff --git a/tests/Makefile.sources b/tests/Makefile.sources
> index 6d081c3..7c6de2f 100644
> --- a/tests/Makefile.sources
> +++ b/tests/Makefile.sources
> @@ -211,6 +211,7 @@ TESTS_progs = \
>  	kms_pwrite_crc \
>  	kms_sink_crc_basic \
>  	prime_udl \
> +	perf \
>  	$(NULL)
>  
>  # IMPORTANT: The ZZ_ tests need to be run last!
> diff --git a/tests/perf.c b/tests/perf.c
> new file mode 100644
> index 0000000..4762e36
> --- /dev/null
> +++ b/tests/perf.c
> @@ -0,0 +1,2220 @@
> +/*
> + * Copyright © 2016 Intel Corporation
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
> + * IN THE SOFTWARE.
> + *
> + */
> +
> +#include <stdlib.h>
> +#include <stdio.h>
> +#include <string.h>
> +#include <fcntl.h>
> +#include <inttypes.h>
> +#include <errno.h>
> +#include <sys/stat.h>
> +#include <sys/time.h>
> +#include <sys/times.h>
> +#include <sys/types.h>
> +#include <dirent.h>
> +#include <time.h>
> +#include <poll.h>
> +#include <math.h>
> +
> +#include "igt.h"
> +#include "drm.h"
> +
> +IGT_TEST_DESCRIPTION("Test the i915 perf metrics streaming interface");
> +
> +#define GEN6_MI_REPORT_PERF_COUNT ((0x28 << 23) | (3 - 2))
> +
> +#define GFX_OP_PIPE_CONTROL     ((3 << 29) | (3 << 27) | (2 << 24))
> +#define PIPE_CONTROL_CS_STALL           (1 << 20)
> +#define PIPE_CONTROL_GLOBAL_SNAPSHOT_COUNT_RESET        (1 << 19)
> +#define PIPE_CONTROL_TLB_INVALIDATE     (1 << 18)
> +#define PIPE_CONTROL_SYNC_GFDT          (1 << 17)
> +#define PIPE_CONTROL_MEDIA_STATE_CLEAR  (1 << 16)
> +#define PIPE_CONTROL_NO_WRITE           (0 << 14)
> +#define PIPE_CONTROL_WRITE_IMMEDIATE    (1 << 14)
> +#define PIPE_CONTROL_WRITE_DEPTH_COUNT  (2 << 14)
> +#define PIPE_CONTROL_WRITE_TIMESTAMP    (3 << 14)
> +#define PIPE_CONTROL_DEPTH_STALL        (1 << 13)
> +#define PIPE_CONTROL_RENDER_TARGET_FLUSH (1 << 12)
> +#define PIPE_CONTROL_INSTRUCTION_INVALIDATE (1 << 11)
> +#define PIPE_CONTROL_TEXTURE_CACHE_INVALIDATE   (1 << 10) /* GM45+ only */
> +#define PIPE_CONTROL_ISP_DIS            (1 << 9)
> +#define PIPE_CONTROL_INTERRUPT_ENABLE   (1 << 8)
> +#define PIPE_CONTROL_FLUSH_ENABLE       (1 << 7) /* Gen7+ only */
> +/* GT */
> +#define PIPE_CONTROL_DATA_CACHE_INVALIDATE      (1 << 5)
> +#define PIPE_CONTROL_VF_CACHE_INVALIDATE        (1 << 4)
> +#define PIPE_CONTROL_CONST_CACHE_INVALIDATE     (1 << 3)
> +#define PIPE_CONTROL_STATE_CACHE_INVALIDATE     (1 << 2)
> +#define PIPE_CONTROL_STALL_AT_SCOREBOARD        (1 << 1)
> +#define PIPE_CONTROL_DEPTH_CACHE_FLUSH          (1 << 0)
> +#define PIPE_CONTROL_PPGTT_WRITE        (0 << 2)
> +#define PIPE_CONTROL_GLOBAL_GTT_WRITE   (1 << 2)
> +
> +#define NSEC_PER_SEC 1000000000ull
> +
> +static struct {
> +        const char *name;
> +        uint64_t id;
> +        size_t size;
> +        int a_off; /* bytes */
> +        int n_a;
> +        int first_a;
> +        int b_off;
> +        int n_b;
> +        int c_off;
> +        int n_c;
> +} hsw_oa_formats[] = {
> +        { "A13", I915_OA_FORMAT_A13, .size = 64,
> +                .a_off = 12, .n_a = 13 },
> +        { "A29", I915_OA_FORMAT_A29, .size = 128,
> +                .a_off = 12, .n_a = 29 },
> +        { "A13_B8_C8", I915_OA_FORMAT_A13_B8_C8, .size = 128,
> +                .a_off = 12, .n_a = 13,
> +                .b_off = 64, .n_b = 8,
> +                .c_off = 96, .n_c = 8 },
> +        { "A45_B8_C8", I915_OA_FORMAT_A45_B8_C8, .size = 256,
> +                .a_off = 12,  .n_a = 45,
> +                .b_off = 192, .n_b = 8,
> +                .c_off = 224, .n_c = 8 },
> +        { "B4_C8", I915_OA_FORMAT_B4_C8, .size = 64,
> +                .b_off = 16, .n_b = 4,
> +                .c_off = 32, .n_c = 8 },
> +        { "B4_C8_A16", I915_OA_FORMAT_B4_C8_A16, .size = 128,
> +                .b_off = 16, .n_b = 4,
> +                .c_off = 32, .n_c = 8,
> +                .a_off = 60, .n_a = 16, .first_a = 29 },
> +        { "C4_B8", I915_OA_FORMAT_C4_B8, .size = 64,
> +                .c_off = 16, .n_c = 4,
> +                .b_off = 28, .n_b = 8 },
> +};
> +
> +static bool hsw_undefined_a_counters[45] = {
> +        [4] = true,
> +        [6] = true,
> +        [9] = true,
> +        [11] = true,
> +        [14] = true,
> +        [16] = true,
> +        [19] = true,
> +        [21] = true,
> +        [24] = true,
> +        [26] = true,
> +        [29] = true,
> +        [31] = true,
> +        [34] = true,
> +        [43] = true,
> +        [44] = true,
> +};
> +
> +static int drm_fd;
> +static uint32_t devid;
> +static int device;
> +
> +static uint64_t hsw_render_basic_id = UINT64_MAX;
> +static uint64_t gt_min_freq_mhz_saved = 0;
> +static uint64_t gt_max_freq_mhz_saved = 0;
> +static uint64_t gt_min_freq_mhz = 0;
> +static uint64_t gt_max_freq_mhz = 0;
> +
> +static uint64_t timestamp_frequency = 12500000;
> +
> +static igt_render_copyfunc_t render_copy = NULL;
> +
> +static int
> +__perf_open(int fd, struct drm_i915_perf_open_param *param)
> +{
> +        int ret = igt_ioctl(fd, DRM_IOCTL_I915_PERF_OPEN, param);
> +
> +        igt_assert(ret >= 0);
> +        errno = 0;
> +
> +        return ret;
> +}
> +
> +static int
> +lookup_format(int i915_perf_fmt_id)
> +{
> +        for (int i = 0; i < ARRAY_SIZE(hsw_oa_formats); i++)
> +                if (hsw_oa_formats[i].id == i915_perf_fmt_id)
> +                        return i;
> +
> +        igt_assert(!"reached");
> +}
> +
> +static bool
> +try_read_u64_file(const char *file, uint64_t *val)
> +{
> +        char buf[32];
> +        int fd, n;
> +
> +        fd = open(file, O_RDONLY);
> +        if (fd < 0)
> +                return false;
> +
> +        while ((n = read(fd, buf, sizeof(buf) - 1)) < 0 && errno == EINTR)
> +                ;
> +        igt_assert(n >= 0);
> +
> +        close(fd);
> +
> +        buf[n] = '\0';
> +        *val = strtoull(buf, NULL, 0);
> +
> +        return true;
> +}
> +
> +static uint64_t
> +read_u64_file(const char *file)
> +{
> +        uint64_t val;
> +
> +        igt_assert_eq(try_read_u64_file(file, &val), true);
> +
> +        return val;
> +}
> +
> +static void
> +write_u64_file(const char *file, uint64_t val)
> +{
> +        char buf[32];
> +        int fd, len, ret;
> +
> +        fd = open(file, O_WRONLY);
> +        igt_assert(fd >= 0);
> +
> +        len = snprintf(buf, sizeof(buf), "%"PRIu64, val);
> +        igt_assert(len > 0);
> +
> +        while ((ret = write(fd, buf, len)) < 0 && errno == EINTR)
> +                ;
> +        igt_assert_eq(ret, len);
> +
> +        close(fd);
> +}
> +
> +static uint64_t
> +sysfs_read(const char *file)
> +{
> +        char buf[512];
> +
> +        snprintf(buf, sizeof(buf), "/sys/class/drm/card%d/%s", device, file);
> +
> +        return read_u64_file(buf);
> +}
> +
> +static void
> +sysfs_write(const char *file, uint64_t val)
> +{
> +        char buf[512];
> +
> +        snprintf(buf, sizeof(buf), "/sys/class/drm/card%d/%s", device, file);
> +
> +        write_u64_file(buf, val);
> +}
> +
> +static char *
> +read_debugfs_record(const char *file, const char *key)
> +{
> +        FILE *fp;
> +        char *line = NULL;
> +        size_t line_buf_size = 0;
> +        int len = 0;
> +        int key_len = strlen(key);
> +        char *value = NULL;
> +
> +        fp = igt_debugfs_fopen(file, "r");
> +        igt_require(fp);
> +
> +        while ((len = getline(&line, &line_buf_size, fp)) > 0) {
> +
> +                if (line[len - 1] == '\n')
> +                        line[len - 1] = '\0';
> +
> +                if (strncmp(key, line, key_len) == 0 &&
> +                    line[key_len] == ':' &&
> +                    line[key_len + 1] == ' ')
> +                {
> +                        value = strdup(line + key_len + 2);
> +                        goto done;
Why not just break here, then we don't need the label ? Or perhaps you
meant to whack an igt_assert(!"reached") inbetween ?

> +                }
> +        }
> +
> +done:
> +        free(line);
> +        if (fp)
> +                fclose(fp);
> +        return value;
> +}
> +
> +static uint64_t
> +read_debugfs_u64_record(const char *file, const char *key)
> +{
> +        char *str_val = read_debugfs_record(file, key);
> +        uint64_t val;
> +
> +        igt_require(str_val);
> +
> +        val = strtoull(str_val, NULL, 0);
> +        free(str_val);
> +
> +        return val;
> +}
> +
> +static bool
> +lookup_hsw_render_basic_id(void)
> +{
> +        char buf[256];
> +
> +        snprintf(buf, sizeof(buf),
> +                 "/sys/class/drm/card%d/metrics/403d8832-1a27-4aa6-a64e-f5389ce7b212/id",
> +                 device);
> +
> +        return try_read_u64_file(buf, &hsw_render_basic_id);
> +}
> +
> +static void
> +gt_frequency_range_save(void)
> +{
> +        gt_min_freq_mhz_saved = sysfs_read("gt_min_freq_mhz");
> +        gt_max_freq_mhz_saved = sysfs_read("gt_max_freq_mhz");
> +
> +        gt_min_freq_mhz = gt_min_freq_mhz_saved;
> +        gt_max_freq_mhz = gt_max_freq_mhz_saved;
> +}
> +
> +static void
> +gt_frequency_pin(int gt_freq_mhz)
> +{
> +        igt_debug("requesting pinned GT freq = %dmhz\n", gt_freq_mhz);
> +
> +        if (gt_freq_mhz > gt_max_freq_mhz) {
> +                sysfs_write("gt_max_freq_mhz", gt_freq_mhz);
> +                sysfs_write("gt_min_freq_mhz", gt_freq_mhz);
> +        } else {
> +                sysfs_write("gt_min_freq_mhz", gt_freq_mhz);
> +                sysfs_write("gt_max_freq_mhz", gt_freq_mhz);
> +        }
> +        gt_min_freq_mhz = gt_freq_mhz;
> +        gt_max_freq_mhz = gt_freq_mhz;
> +}
> +
> +static void
> +gt_frequency_range_restore(void)
> +{
> +        igt_debug("restoring GT frequency range: min = %dmhz, max =%dmhz, current: min=%dmhz, max=%dmhz\n",
> +                  (int)gt_min_freq_mhz_saved,
> +                  (int)gt_max_freq_mhz_saved,
> +                  (int)gt_min_freq_mhz,
> +                  (int)gt_max_freq_mhz);
> +
> +        /* Assume current min/max are the same */
> +        if (gt_min_freq_mhz_saved > gt_max_freq_mhz) {
> +                sysfs_write("gt_max_freq_mhz", gt_max_freq_mhz_saved);
> +                sysfs_write("gt_min_freq_mhz", gt_min_freq_mhz_saved);
> +        } else {
> +                sysfs_write("gt_min_freq_mhz", gt_min_freq_mhz_saved);
> +                sysfs_write("gt_max_freq_mhz", gt_max_freq_mhz_saved);
> +        }
> +
> +        gt_min_freq_mhz = gt_min_freq_mhz_saved;
> +        gt_max_freq_mhz = gt_max_freq_mhz_saved;
> +}
> +
> +static uint64_t
> +timebase_scale(uint32_t u32_delta)
> +{
> +        return ((uint64_t)u32_delta * NSEC_PER_SEC) / timestamp_frequency;
> +}
> +
> +/* CAP_SYS_ADMIN is required to open system wide metrics, unless the system
> + * control parameter dev.i915.perf_stream_paranoid == 0 */
> +static void
> +test_system_wide_paranoid(void)
> +{
> +        igt_fork(child, 1) {
> +                uint64_t properties[] = {
> +                        /* Include OA reports in samples */
> +                        DRM_I915_PERF_PROP_SAMPLE_OA, true,
> +
> +                        /* OA unit configuration */
> +                        DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
> +                        DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
> +                        DRM_I915_PERF_PROP_OA_EXPONENT, 13, /* 1 millisecond */
> +                };
> +                struct drm_i915_perf_open_param param = {
> +                        .flags = I915_PERF_FLAG_FD_CLOEXEC |
> +                                I915_PERF_FLAG_FD_NONBLOCK,
> +                        .num_properties = sizeof(properties) / 16,
> +                        .properties_ptr = (uint64_t)properties,
> +                };
> +
> +                write_u64_file("/proc/sys/dev/i915/perf_stream_paranoid", 1);
> +
> +                igt_drop_root();
> +
> +                do_ioctl_err(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param, EACCES);
> +        }
> +
> +        igt_waitchildren();
> +
> +        igt_fork(child, 1) {
> +                uint64_t properties[] = {
> +                        /* Include OA reports in samples */
> +                        DRM_I915_PERF_PROP_SAMPLE_OA, true,
> +
> +                        /* OA unit configuration */
> +                        DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
> +                        DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
> +                        DRM_I915_PERF_PROP_OA_EXPONENT, 13, /* 1 millisecond */
> +                };
> +                struct drm_i915_perf_open_param param = {
> +                        .flags = I915_PERF_FLAG_FD_CLOEXEC |
> +                                I915_PERF_FLAG_FD_NONBLOCK,
> +                        .num_properties = sizeof(properties) / 16,
> +                        .properties_ptr = (uint64_t)properties,
> +                };
> +                int stream_fd;
> +
> +                write_u64_file("/proc/sys/dev/i915/perf_stream_paranoid", 0);
> +
> +                igt_drop_root();
> +
> +                stream_fd = __perf_open(drm_fd, &param);
> +                close(stream_fd);
> +        }
> +
> +        igt_waitchildren();
> +
> +        /* leave in paranoid state */
> +        write_u64_file("/proc/sys/dev/i915/perf_stream_paranoid", 1);
> +}
> +
> +static void
> +test_invalid_open_flags(void)
> +{
> +        uint64_t properties[] = {
> +                /* Include OA reports in samples */
> +                DRM_I915_PERF_PROP_SAMPLE_OA, true,
> +
> +                /* OA unit configuration */
> +                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
> +                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
> +                DRM_I915_PERF_PROP_OA_EXPONENT, 13, /* 1 millisecond */
> +        };
> +        struct drm_i915_perf_open_param param = {
> +                .flags = ~0, /* Undefined flag bits set! */
> +                .num_properties = sizeof(properties) / 16,
> +                .properties_ptr = (uint64_t)properties,
> +        };
> +
> +        do_ioctl_err(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param, EINVAL);
> +}
> +
> +static void
> +test_invalid_oa_metric_set_id(void)
> +{
> +        uint64_t properties[] = {
> +                /* Include OA reports in samples */
> +                DRM_I915_PERF_PROP_SAMPLE_OA, true,
> +
> +                /* OA unit configuration */
> +                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
> +                DRM_I915_PERF_PROP_OA_EXPONENT, 13, /* 1 millisecond */
> +                DRM_I915_PERF_PROP_OA_METRICS_SET, UINT64_MAX,
> +        };
> +        struct drm_i915_perf_open_param param = {
> +                .flags = I915_PERF_FLAG_FD_CLOEXEC |
> +                        I915_PERF_FLAG_FD_NONBLOCK,
> +                .num_properties = sizeof(properties) / 16,
> +                .properties_ptr = (uint64_t)properties,
> +        };
> +        int stream_fd;
> +
> +        do_ioctl_err(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param, EINVAL);
> +
> +        properties[ARRAY_SIZE(properties) - 1] = 0; /* ID 0 is also be reserved as invalid */
> +        do_ioctl_err(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param, EINVAL);
> +
> +        /* Check that we aren't just seeing false positives... */
> +        properties[ARRAY_SIZE(properties) - 1] = hsw_render_basic_id;
> +        stream_fd = __perf_open(drm_fd, &param);
> +        close(stream_fd);
> +
> +        /* There's no valid default OA metric set ID... */
> +        param.num_properties--;
> +        do_ioctl_err(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param, EINVAL);
> +}
> +
> +static void
> +test_invalid_oa_format_id(void)
> +{
> +        uint64_t properties[] = {
> +                /* Include OA reports in samples */
> +                DRM_I915_PERF_PROP_SAMPLE_OA, true,
> +
> +                /* OA unit configuration */
> +                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
> +                DRM_I915_PERF_PROP_OA_EXPONENT, 13, /* 1 millisecond */
> +                DRM_I915_PERF_PROP_OA_FORMAT, UINT64_MAX,
> +        };
> +        struct drm_i915_perf_open_param param = {
> +                .flags = I915_PERF_FLAG_FD_CLOEXEC |
> +                        I915_PERF_FLAG_FD_NONBLOCK,
> +                .num_properties = sizeof(properties) / 16,
> +                .properties_ptr = (uint64_t)properties,
> +        };
> +        int stream_fd;
> +
> +        do_ioctl_err(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param, EINVAL);
> +
> +        properties[ARRAY_SIZE(properties) - 1] = 0; /* ID 0 is also be reserved as invalid */
> +        do_ioctl_err(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param, EINVAL);
> +
> +        /* Check that we aren't just seeing false positives... */
> +        properties[ARRAY_SIZE(properties) - 1] = I915_OA_FORMAT_A45_B8_C8;
> +        stream_fd = __perf_open(drm_fd, &param);
> +        close(stream_fd);
> +
> +        /* There's no valid default OA format... */
> +        param.num_properties--;
> +        do_ioctl_err(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param, EINVAL);
> +}
> +
> +static void
> +test_missing_sample_flags(void)
> +{
> +        uint64_t properties[] = {
> +                /* No _PROP_SAMPLE_xyz flags */
> +
> +                /* OA unit configuration */
> +                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
> +                DRM_I915_PERF_PROP_OA_EXPONENT, 13, /* 1 millisecond */
> +                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
> +        };
> +        struct drm_i915_perf_open_param param = {
> +                .flags = I915_PERF_FLAG_FD_CLOEXEC,
> +                .num_properties = sizeof(properties) / 16,
> +                .properties_ptr = (uint64_t)properties,
> +        };
> +
> +        do_ioctl_err(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param, EINVAL);
> +}
> +
> +static void
> +read_2_oa_reports(int stream_fd,
> +                  uint64_t format_id,
> +                  size_t format_size,
> +                  int exponent,
> +                  uint32_t *oa_report0,
> +                  uint32_t *oa_report1,
> +                  bool timer_only)
> +{
> +        size_t sample_size = (sizeof(struct drm_i915_perf_record_header) +
> +                              format_size);
> +        const struct drm_i915_perf_record_header *header;
> +        uint32_t exponent_mask = (1 << (exponent + 1)) - 1;
> +
> +        /* Note: we allocate a large buffer so that each read() iteration
> +         * should scrape *all* pending records.
> +         *
> +         * The largest buffer the OA unit supports is 16MB and the smallest
> +         * OA report format is 64bytes allowing up to 262144 reports to
> +         * be buffered.
> +         *
> +         * Being sure we are fetching all buffered reports allows us to
> +         * potentially throw away / skip all reports whenever we see
> +         * a _REPORT_LOST notification as a way of being sure are
> +         * measurements aren't skewed by a lost report.
> +         *
> +         * Note: that is is useful for some tests but also not something
> +         * applications would be expected to resort to. Lost reports are
> +         * somewhat unpredictable but typically don't pose a problem - except
> +         * to indicate that the OA unit may be over taxed if lots of reports
> +         * are being lost.
> +         */
> +        int buf_size = 262144 * (64 + sizeof(struct drm_i915_perf_record_header));
> +        uint8_t *buf = malloc(buf_size);
> +        int n = 0;
> +
> +        for (int i = 0; i < 1000; i++) {
> +                ssize_t len;
> +
> +                while ((len = read(stream_fd, buf, buf_size)) < 0 &&
> +                       errno == EINTR)
> +                        ;
> +
> +                igt_assert(len > 0);
> +
> +                for (size_t offset = 0; offset < len; offset += header->size) {
> +                        const uint32_t *report;
> +
> +                        header = (void *)(buf + offset);
> +
> +                        igt_assert_eq(header->pad, 0); /* Reserved */
> +
> +                        /* Currently the only test that should ever expect to
> +                         * see a _BUFFER_LOST error is the buffer_fill test,
> +                         * otherwise something bad has probably happened...
> +                         */
> +                        igt_assert_neq(header->type, DRM_I915_PERF_RECORD_OA_BUFFER_LOST);
> +
> +                        /* At high sampling frequencies the OA HW might not be
> +                         * able to cope with all write requests and will notify
> +                         * us that a report was lost. We restart our read of
> +                         * two sequential reports due to the timeline blip this
> +                         * implies
> +                         */
> +                        if (header->type == DRM_I915_PERF_RECORD_OA_REPORT_LOST) {
> +                                igt_debug("read restart: OA trigger collision / report lost\n");
> +                                n = 0;
> +
> +                                /* XXX: break, because we don't know where
> +                                 * within the series of already read reports
> +                                 * there could be a blip from the lost report.
> +                                 */
> +                                break;
> +                        }
> +
> +                        /* Currently the only other record type expected is a
> +                         * _SAMPLE. Notably this test will need updating if
> +                         * i915-perf is extended in the future with additional
> +                         * record types.
> +                         */
> +                        igt_assert_eq(header->type, DRM_I915_PERF_RECORD_SAMPLE);
> +
> +                        igt_assert_eq(header->size, sample_size);
> +
> +                        report = (const void *)(header + 1);
> +
> +                        igt_debug("read report: reason = %x, timestamp = %x, exponent mask=%x\n",
> +                                  report[0], report[1], exponent_mask);
> +
> +                        /* Don't expect zero for timestamps */
> +                        igt_assert_neq(report[1], 0);
> +
> +                        if (timer_only) {
> +                                /* For Haswell we don't have a documented
> +                                 * report reason field (though empirically
> +                                 * report[0] bit 10 does seem to correlate with
> +                                 * a timer trigger reason) so we instead infer
> +                                 * which reports are timer triggered by
> +                                 * checking if the least significant bits are
> +                                 * zero and the exponent bit is set.
> +                                 */
> +                                if ((report[1] & exponent_mask) != (1 << exponent)) {
> +                                        igt_debug("skipping non timer report reason=%x\n",
> +                                                  report[0]);
> +
> +                                        /* Also assert our hypothesis about the
> +                                         * reason bit...
> +                                         */
> +                                        igt_assert_eq(report[0] & (1 << 10), 0);
> +                                        continue;
> +                                }
> +                        }
> +
> +                        if (n++ == 0)
> +                                memcpy(oa_report0, report, format_size);
> +                        else {
> +                                memcpy(oa_report1, report, format_size);
> +                                free(buf);
> +                                return;
> +                        }
> +                }
> +        }
> +
> +        free(buf);
> +
> +        igt_assert(!"reached");
> +}
> +
> +static void
> +open_and_read_2_oa_reports(uint64_t format_id,
> +                           size_t format_size,
> +                           int exponent,
> +                           uint32_t *oa_report0,
> +                           uint32_t *oa_report1,
> +                           bool timer_only)
> +{
> +        uint64_t properties[] = {
> +                /* Include OA reports in samples */
> +                DRM_I915_PERF_PROP_SAMPLE_OA, true,
> +
> +                /* OA unit configuration */
> +                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
> +                DRM_I915_PERF_PROP_OA_FORMAT, format_id,
> +                DRM_I915_PERF_PROP_OA_EXPONENT, exponent,
> +
> +        };
> +        struct drm_i915_perf_open_param param = {
> +                .flags = I915_PERF_FLAG_FD_CLOEXEC,
> +                .num_properties = sizeof(properties) / 16,
> +                .properties_ptr = (uint64_t)properties,
> +        };
> +        int stream_fd = __perf_open(drm_fd, &param);
> +
> +        read_2_oa_reports(stream_fd, format_id, format_size, exponent,
> +                          oa_report0, oa_report1, timer_only);
> +
> +        close(stream_fd);
> +}
> +
> +static void
> +print_reports(uint32_t *oa_report0, uint32_t *oa_report1, int fmt)
> +{
> +        uint32_t *a0, *b0, *c0;
> +        uint32_t *a1, *b1, *c1;
> +
> +        /* Not ideal naming here with a0 or a1
> +         * differentiating report0 or 1 not A counter 0 or 1....
> +         */
> +        a0 = (uint32_t *)(((uint8_t *)oa_report0) + hsw_oa_formats[fmt].a_off);
> +        b0 = (uint32_t *)(((uint8_t *)oa_report0) + hsw_oa_formats[fmt].b_off);
> +        c0 = (uint32_t *)(((uint8_t *)oa_report0) + hsw_oa_formats[fmt].c_off);
> +
> +        a1 = (uint32_t *)(((uint8_t *)oa_report1) + hsw_oa_formats[fmt].a_off);
> +        b1 = (uint32_t *)(((uint8_t *)oa_report1) + hsw_oa_formats[fmt].b_off);
> +        c1 = (uint32_t *)(((uint8_t *)oa_report1) + hsw_oa_formats[fmt].c_off);
> +
> +        igt_debug("TIMESTAMP: 1st = %"PRIu32", 2nd = %"PRIu32", delta = %"PRIu32"\n",
> +                  oa_report0[1], oa_report1[1], oa_report1[1] - oa_report0[1]);
> +
> +        if (hsw_oa_formats[fmt].n_c) {
> +                igt_debug("CLOCK: 1st = %"PRIu32", 2nd = %"PRIu32", delta = %"PRIu32"\n",
> +                          c0[2], c1[2], c1[2] - c0[2]);
> +        } else
> +                igt_debug("CLOCK = N/A\n");
> +
> +        for (int j = hsw_oa_formats[fmt].first_a;
> +             j < hsw_oa_formats[fmt].n_a;
> +             j++)
> +        {
> +                uint32_t delta = a1[j] - a0[j];
> +
> +                if (hsw_undefined_a_counters[j])
> +                        continue;
> +
> +                igt_debug("A%d: 1st = %"PRIu32", 2nd = %"PRIu32", delta = %"PRIu32"\n",
> +                          j, a0[j], a1[j], delta);
> +        }
> +
> +        for (int j = 0; j < hsw_oa_formats[fmt].n_b; j++) {
> +                uint32_t delta = b1[j] - b0[j];
> +                igt_debug("B%d: 1st = %"PRIu32", 2nd = %"PRIu32", delta = %"PRIu32"\n",
> +                          j, b0[j], b1[j], delta);
> +        }
> +
> +        for (int j = 0; j < hsw_oa_formats[fmt].n_c; j++) {
> +                uint32_t delta = c1[j] - c0[j];
> +                igt_debug("C%d: 1st = %"PRIu32", 2nd = %"PRIu32", delta = %"PRIu32"\n",
> +                          j, c0[j], c1[j], delta);
> +        }
> +}
> +
> +static void
> +test_oa_formats(void)
> +{
> +        int oa_exponent = 13;
> +
> +        for (int i = 0; i < ARRAY_SIZE(hsw_oa_formats); i++) {
> +                uint32_t oa_report0[64];
> +                uint32_t oa_report1[64];
> +                uint32_t *a0, *b0, *c0;
> +                uint32_t *a1, *b1, *c1;
> +                uint32_t time_delta;
> +                uint32_t clock_delta;
> +                uint32_t max_delta;
> +
> +                igt_debug("Checking OA format %s\n", hsw_oa_formats[i].name);
> +
> +                open_and_read_2_oa_reports(hsw_oa_formats[i].id,
> +                                           hsw_oa_formats[i].size,
> +                                           oa_exponent,
> +                                           oa_report0,
> +                                           oa_report1,
> +                                           false); /* timer reports only */
> +
> +                print_reports(oa_report0, oa_report1, i);
> +
> +                a0 = (uint32_t *)(((uint8_t *)oa_report0) + hsw_oa_formats[i].a_off);
> +                b0 = (uint32_t *)(((uint8_t *)oa_report0) + hsw_oa_formats[i].b_off);
> +                c0 = (uint32_t *)(((uint8_t *)oa_report0) + hsw_oa_formats[i].c_off);
> +
> +                a1 = (uint32_t *)(((uint8_t *)oa_report1) + hsw_oa_formats[i].a_off);
> +                b1 = (uint32_t *)(((uint8_t *)oa_report1) + hsw_oa_formats[i].b_off);
> +                c1 = (uint32_t *)(((uint8_t *)oa_report1) + hsw_oa_formats[i].c_off);
> +
> +                time_delta = timebase_scale(oa_report1[1] - oa_report0[1]);
> +                igt_assert_neq(time_delta, 0);
> +
> +                /* C2 corresponds to a clock counter for this metric set but
> +                 * it's not included in all of the formats. */
> +                if (hsw_oa_formats[i].n_c) {
> +                        uint64_t freq;
> +
> +                        /* The first report might have a clock count of zero
> +                         * but we wouldn't expect that in the second report...
> +                         */
> +                        igt_assert_neq(c1[2], 0);
> +
> +                        clock_delta = c1[2] - c0[2];
> +                        igt_assert_neq(clock_delta, 0);
> +
> +                        freq = ((uint64_t)clock_delta * 1000) / time_delta;
> +                        igt_debug("freq = %"PRIu64"\n", freq);
> +
> +                        igt_assert(freq <= gt_max_freq_mhz);
> +                } else {
> +                        /* Assume running at max freq for sake of
> +                         * below sanity check on counters... */
> +                        clock_delta = (gt_max_freq_mhz *
> +                                       (uint64_t)time_delta) / 1000;
> +                }
> +
> +                igt_debug("clock delta = %"PRIu32"\n", clock_delta);
> +
> +                /* The maximum rate for any HSW counter =
> +                 *   clock_delta * 40 EUs
> +                 *
> +                 * Sanity check that no counters exceed this delta.
> +                 */
> +                max_delta = clock_delta * 40;
> +
> +                for (int j = hsw_oa_formats[i].first_a;
> +                     j < hsw_oa_formats[i].n_a;
> +                     j++)
> +                {
> +                        uint32_t delta = a1[j] - a0[j];
> +
> +                        if (hsw_undefined_a_counters[j])
> +                                continue;
> +
> +                        igt_debug("A%d: delta = %"PRIu32"\n", j, delta);
> +                        igt_assert(delta <= max_delta);
> +                }
> +
> +                for (int j = 0; j < hsw_oa_formats[i].n_b; j++) {
> +                        uint32_t delta = b1[j] - b0[j];
> +                        igt_debug("B%d: delta = %"PRIu32"\n", j, delta);
> +                        igt_assert(delta <= max_delta);
> +                }
> +
> +                for (int j = 0; j < hsw_oa_formats[i].n_c; j++) {
> +                        uint32_t delta = c1[j] - c0[j];
> +                        igt_debug("C%d: delta = %"PRIu32"\n", j, delta);
> +                        igt_assert(delta <= max_delta);
> +                }
> +        }
> +}
> +
> +static void
> +test_oa_exponents(int gt_freq_mhz)
> +{
> +        /* XXX: Note that gt_min/max_freq_mhz don't seem to be a reliable
> +         * mechanism for fixing the gpu frequency and since these unit tests
> +         * are focused on the OA unit not the ability to pin the frequency we
> +         * read back the current frequency for each iteration of this test to
> +         * take this into account.
> +         */
> +        gt_frequency_pin(gt_freq_mhz);
> +
> +        igt_debug("Testing OA timer exponents with requested GT frequency = %dmhz\n",
> +                  gt_freq_mhz);
> +
> +        /* It's asking a lot to sample with a 160 nanosecond period and the
> +         * test can fail due to buffer overflows if it wasn't possible to
> +         * keep up, so we don't start from an exponent of zero...
> +         */
> +        for (int i = 2; i < 20; i++) {
> +                uint32_t expected_timestamp_delta;
> +                uint32_t timestamp_delta;
> +                uint32_t oa_report0[64];
> +                uint32_t oa_report1[64];
> +                uint32_t *c0, *c1;
> +                uint32_t time_delta;
> +                uint32_t clock_delta;
> +                uint32_t freq;
> +                int n_freq_matches = 0;
> +
> +                /* The exponent is effectively selecting a bit in the timestamp
> +                 * to trigger reports on and so in practice we expect the raw
> +                 * timestamp deltas for periodic reports to exactly match the
> +                 * value of next bit.
> +                 */
> +                expected_timestamp_delta = 2 << i;
> +
> +                for (int j = 0; j < 10; j++) {
> +                        gt_freq_mhz = sysfs_read("gt_act_freq_mhz");
> +
> +                        igt_debug("ITER %d: testing OA exponent %d with GT freq = %dmhz\n",
> +                                  j, i, gt_freq_mhz);
> +
> +                        open_and_read_2_oa_reports(I915_OA_FORMAT_A45_B8_C8, 256,
> +                                                   i, /* exponent */
> +                                                   oa_report0,
> +                                                   oa_report1,
> +                                                   true); /* timer triggered
> +                                                             reports only */
> +
> +                        timestamp_delta = oa_report1[1] - oa_report0[1];
> +                        igt_assert_neq(timestamp_delta, 0);
> +
> +                        if (timestamp_delta != expected_timestamp_delta) {
> +                                igt_debug("timestamp0 = %u/0x%x\n",
> +                                          oa_report0[1], oa_report0[1]);
> +                                igt_debug("timestamp1 = %u/0x%x\n",
> +                                          oa_report1[1], oa_report1[1]);
> +                        }
> +
> +                        igt_assert_eq(timestamp_delta, expected_timestamp_delta);
> +
> +                        c0 = (uint32_t *)(((uint8_t *)oa_report0) + 224 /* C offset */);
> +                        c1 = (uint32_t *)(((uint8_t *)oa_report1) + 224 /* C offset */);
Most definitely sprinkle a comment here for what the custom counter
actually is, "The total number of GPU core clocks elapsed during the
measurement."

> +                        clock_delta = c1[2] - c0[2];
> +
> +                        time_delta = timebase_scale(timestamp_delta);
> +
> +                        freq = ((uint64_t)clock_delta * 1000) / time_delta;
> +                        igt_debug("ITER %d: time delta = %"PRIu32"(ns) clock delta = %"PRIu32" freq = %"PRIu32"(mhz)\n",
> +                                  j, time_delta, clock_delta, freq);
> +
> +                        if (freq == gt_freq_mhz)
> +                                n_freq_matches++;
> +                }
> +
> +                igt_debug("number of iterations with expected clock frequency = %d\n",
> +                          n_freq_matches);
> +
> +                /* Don't assert the calculated frequency for extremely short
> +                 * durations... */
> +                if (i > 3)
> +                        igt_assert(n_freq_matches >= 7);
> +        }
> +
> +        gt_frequency_range_restore();
> +}
> +
> +/* The OA exponent selects a timestamp counter bit to trigger reports on.
> + *
> + * With a 64bit timestamp and least significant bit approx == 80ns then the MSB
> + * equates to > 40 thousand years and isn't exposed via the i915 perf interface.
> + *
> + * The max exponent exposed is expected to be 31, which is still a fairly
> + * ridiculous period (>5min) but is the maximum exponent where it's still
> + * possible to use periodic sampling as a means for tracking the overflow of
> + * 32bit OA report timestamps.
> + */
> +static void
> +test_invalid_oa_exponent(void)
> +{
> +        uint64_t properties[] = {
> +                /* Include OA reports in samples */
> +                DRM_I915_PERF_PROP_SAMPLE_OA, true,
> +
> +                /* OA unit configuration */
> +                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
> +                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
> +                DRM_I915_PERF_PROP_OA_EXPONENT, 31, /* maximum exponent expected
> +                                                       to be accepted */
> +        };
> +        struct drm_i915_perf_open_param param = {
> +                .flags = I915_PERF_FLAG_FD_CLOEXEC,
> +                .num_properties = sizeof(properties) / 16,
> +                .properties_ptr = (uint64_t)properties,
> +        };
> +        int stream_fd = __perf_open(drm_fd, &param);
> +
> +        close(stream_fd);
> +
> +        for (int i = 32; i < 65; i++) {
> +                properties[7] = i;
> +                do_ioctl_err(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param, EINVAL);
> +        }
> +}
> +
> +/* Return the largest OA exponent that will still result in a sampling
> + * frequency higher than the given frequency.
> + */
> +static int
> +max_oa_exponent_for_higher_freq(uint64_t freq)
> +{
> +        /* NB: timebase_scale() takes a uint32_t and an exponent of 30
> +         * would already represent a period of ~3 minutes so there's
> +         * really no need to consider higher exponents.
> +         */
> +        for (int i = 0; i < 30; i++) {
> +                uint64_t oa_period = timebase_scale(2 << i);
> +                uint32_t oa_freq = NSEC_PER_SEC / oa_period;
> +
> +                if (oa_freq <= freq)
> +                        return max(0, i - 1);
> +        }
> +
> +        igt_assert(!"reached");
> +        return -1;
> +}
> +
> +/* The lowest periodic sampling exponent equates to a period of 160 nanoseconds
> + * or a frequency of 6.25MHz which is only possible to request as root by
> + * default. By default the maximum OA sampling rate is 100KHz
> + */
> +static void
> +test_low_oa_exponent_permissions(void)
> +{
> +        int max_freq = read_u64_file("/proc/sys/dev/i915/oa_max_sample_rate");
> +        int bad_exponent = max_oa_exponent_for_higher_freq(max_freq);
> +        int ok_exponent = bad_exponent + 1;
> +        uint64_t properties[] = {
> +                /* Include OA reports in samples */
> +                DRM_I915_PERF_PROP_SAMPLE_OA, true,
> +
> +                /* OA unit configuration */
> +                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
> +                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
> +                DRM_I915_PERF_PROP_OA_EXPONENT, bad_exponent,
> +        };
> +        struct drm_i915_perf_open_param param = {
> +                .flags = I915_PERF_FLAG_FD_CLOEXEC,
> +                .num_properties = sizeof(properties) / 16,
> +                .properties_ptr = (uint64_t)properties,
> +        };
> +        uint64_t oa_period, oa_freq;
> +
> +        igt_assert_eq(max_freq, 100000);
> +
> +        /* Avoid EACCESS errors opening a stream without CAP_SYS_ADMIN */
> +        write_u64_file("/proc/sys/dev/i915/perf_stream_paranoid", 0);
> +
> +        igt_fork(child, 1) {
> +                igt_drop_root();
> +
> +                do_ioctl_err(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param, EACCES);
> +        }
> +
> +        igt_waitchildren();
> +
> +        properties[7] = ok_exponent;
> +
> +        igt_fork(child, 1) {
> +                int stream_fd;
> +
> +                igt_drop_root();
> +
> +                stream_fd = __perf_open(drm_fd, &param);
> +                close(stream_fd);
> +        }
> +
> +        igt_waitchildren();
> +
> +        oa_period = timebase_scale(2 << ok_exponent);
> +        oa_freq = NSEC_PER_SEC / oa_period;
> +        write_u64_file("/proc/sys/dev/i915/oa_max_sample_rate", oa_freq - 100);
> +
> +        igt_fork(child, 1) {
> +                igt_drop_root();
> +
> +                do_ioctl_err(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param, EACCES);
> +        }
> +
> +        igt_waitchildren();
> +
> +        /* restore the defaults */
> +        write_u64_file("/proc/sys/dev/i915/oa_max_sample_rate", 100000);
> +        write_u64_file("/proc/sys/dev/i915/perf_stream_paranoid", 1);
> +}
> +
> +static void
> +test_per_context_mode_unprivileged(void)
> +{
> +        uint64_t properties[] = {
> +                /* Single context sampling */
> +                DRM_I915_PERF_PROP_CTX_HANDLE, UINT64_MAX, /* updated below */
> +
> +                /* Include OA reports in samples */
> +                DRM_I915_PERF_PROP_SAMPLE_OA, true,
> +
> +                /* OA unit configuration */
> +                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
> +                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
> +                DRM_I915_PERF_PROP_OA_EXPONENT, 13, /* 1 millisecond */
> +        };
> +        struct drm_i915_perf_open_param param = {
> +                .flags = I915_PERF_FLAG_FD_CLOEXEC,
> +                .num_properties = sizeof(properties) / 16,
> +                .properties_ptr = (uint64_t)properties,
> +        };
> +
> +        /* should be default, but just to be sure... */
> +        write_u64_file("/proc/sys/dev/i915/perf_stream_paranoid", 1);
> +
> +        igt_fork(child, 1) {
> +                drm_intel_context *context;
> +                drm_intel_bufmgr *bufmgr;
> +                int stream_fd;
> +
> +                igt_drop_root();
> +
> +                bufmgr = drm_intel_bufmgr_gem_init(drm_fd, 4096);
> +                context = drm_intel_gem_context_create(bufmgr);
> +
> +                igt_assert(context);
> +
> +                properties[1] = drm_intel_gem_context_get_context_id(context);
> +
> +                stream_fd = __perf_open(drm_fd, &param);
> +                close(stream_fd);
Missing drm_intel_gem_context_destroy.
Missing drm_intel_bufmgr_destroy.

> +        }
> +
> +        igt_waitchildren();
> +}
> +
> +static int64_t
> +get_time(void)
> +{
> +        struct timespec ts;
> +
> +        clock_gettime(CLOCK_MONOTONIC, &ts);
> +
> +        return ts.tv_sec * 1000000000 + ts.tv_nsec;
> +}
> +
> +/* Note: The interface doesn't currently provide strict guarantees or control
> + * over the upper bound for how long it might take for a POLLIN event after
> + * some OA report is written by the OA unit.
> + *
> + * The plan is to add a property later that gives some control over the maximum
> + * latency, but for now we expect it is tuned for a fairly low latency
> + * suitable for applications wanting to provide live feedback for captured
> + * metrics.
> + *
> + * At the time of writing this test the driver was using a fixed 200Hz hrtimer
> + * regardless of the OA sampling exponent.
> + *
> + * There is no lower bound since a stream configured for periodic sampling may
> + * still contain other automatically triggered reports.
> + *
> + * What we try and check for here is that blocking reads don't return EAGAIN
> + * and that we aren't spending any significant time burning the cpu in
> + * kernelspace.
> + */
> +static void
> +test_blocking(void)
> +{
> +        /* 40 milliseconds
> +         *
> +         * Having a period somewhat > sysconf(_SC_CLK_TCK) helps to stop
> +         * scheduling (liable to kick in when we make blocking poll()s/reads)
> +         * from interfering with the test.
> +         */
> +        int oa_exponent = 18;
> +        uint64_t properties[] = {
> +                /* Include OA reports in samples */
> +                DRM_I915_PERF_PROP_SAMPLE_OA, true,
> +
> +                /* OA unit configuration */
> +                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
> +                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
> +                DRM_I915_PERF_PROP_OA_EXPONENT, oa_exponent,
> +        };
> +        struct drm_i915_perf_open_param param = {
> +                .flags = I915_PERF_FLAG_FD_CLOEXEC,
> +                .num_properties = sizeof(properties) / 16,
> +                .properties_ptr = (uint64_t)properties,
> +        };
> +        int stream_fd = __perf_open(drm_fd, &param);
> +        uint8_t buf[1024 * 1024];
> +        struct tms start_times;
> +        struct tms end_times;
> +        int64_t user_ns, kernel_ns;
> +        int64_t tick_ns = 1000000000 / sysconf(_SC_CLK_TCK);
> +        int64_t start;
> +        int n = 0;
> +
> +        times(&start_times);
> +
> +        /* Loop for 600ms performing blocking reads while the HW is sampling at
> +         * ~25Hz, with the expectation that we spend most of our time blocked
> +         * in the kernel, and shouldn't be burning cpu cycles in the kernel in
> +         * association with this process (verified by looking at stime before
> +         * and after loop).
> +         */
> +        for (start = get_time(); (get_time() - start) < 600000000; /* nop */) {
> +                int ret;
> +
> +                while ((ret = read(stream_fd, buf, sizeof(buf))) < 0 &&
> +                       errno == EINTR)
> +                        ;
> +
> +                igt_assert(ret > 0);
> +
> +                n++;
> +        }
> +
> +        times(&end_times);
> +
> +        /* Using nanosecond units is fairly silly here, given the tick in-
> +         * precision - ah well, it's consistent with the get_time() units.
> +         */
> +        user_ns = (end_times.tms_utime - start_times.tms_utime) * tick_ns;
> +        kernel_ns = (end_times.tms_stime - start_times.tms_stime) * tick_ns;
> +
> +        igt_debug("%d blocking reads in 500 milliseconds, with 1KHz OA sampling\n", n);
> +        igt_debug("time in userspace = %"PRIu64"ns (start utime = %d, end = %d, ns ticks per sec = %d)\n",
> +                  user_ns, (int)start_times.tms_utime, (int)end_times.tms_utime, (int)tick_ns);
> +        igt_debug("time in kernelspace = %"PRIu64"ns (start stime = %d, end = %d, ns ticks per sec = %d)\n",
> +                  kernel_ns, (int)start_times.tms_stime, (int)end_times.tms_stime, (int)tick_ns);
> +
> +        /* With completely broken blocking (but also not returning an error) we
> +         * could end up with an open loop, hopefully recognisable with > 15
> +         * (600/40)iterations.
> +         */
> +        igt_assert(n <= 15);
> +
> +        /* It's a bit tricky to put a lower limit here, but we expect a
> +         * relatively low latency for seeing reports, while we don't currently
> +         * give any control over this in the api.
> +         *
> +         * Limited to a 5 millisecond latency and 45ms (worst case)
> +         * per-iteration that could give 13.3 iterations. Rounding gives a tiny
> +         * bit more latency slack (6ms)...
> +         */
> +        igt_assert(n > 13);
> +
> +        /* A bit tricky to put a number on this, but we don't expect the kernel
> +         * to use any significant cpu while waiting and given the in precision
> +         * of stime (multiple of CLK_TCK) we expect this to round to zero.
> +         */
> +        igt_assert_eq(kernel_ns, 0);
> +
> +        close(stream_fd);
> +}
> +
> +static void
> +test_polling(void)
> +{
> +        /* 40 milliseconds
> +         *
> +         * Having a period somewhat > sysconf(_SC_CLK_TCK) helps to stop
> +         * scheduling (liable to kick in when we make blocking poll()s/reads)
> +         * from interfering with the test.
> +         */
> +        int oa_exponent = 18;
> +        uint64_t properties[] = {
> +                /* Include OA reports in samples */
> +                DRM_I915_PERF_PROP_SAMPLE_OA, true,
> +
> +                /* OA unit configuration */
> +                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
> +                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
> +                DRM_I915_PERF_PROP_OA_EXPONENT, oa_exponent,
> +        };
> +        struct drm_i915_perf_open_param param = {
> +                .flags = I915_PERF_FLAG_FD_CLOEXEC |
> +                        I915_PERF_FLAG_FD_NONBLOCK,
> +                .num_properties = sizeof(properties) / 16,
> +                .properties_ptr = (uint64_t)properties,
> +        };
> +        int stream_fd = __perf_open(drm_fd, &param);
> +        uint8_t buf[1024 * 1024];
> +        struct tms start_times;
> +        struct tms end_times;
> +        int64_t user_ns, kernel_ns;
> +        int64_t tick_ns = 1000000000 / sysconf(_SC_CLK_TCK);
> +        int64_t start;
> +        int n = 0;
> +
> +        times(&start_times);
> +
> +        /* Loop for 600ms performing blocking polls while the HW is sampling at
> +         * ~25Hz, with the expectation that we spend most of our time blocked
> +         * in the kernel, and shouldn't be burning cpu cycles in the kernel in
> +         * association with this process (verified by looking at stime before
> +         * and after loop).
> +         */
> +        for (start = get_time(); (get_time() - start) < 600000000; /* nop */) {
> +                struct pollfd pollfd = { .fd = stream_fd, .events = POLLIN };
> +                int ret;
> +
> +                while ((ret = poll(&pollfd, 1, -1)) < 0 &&
> +                       errno == EINTR)
> +                        ;
> +                igt_assert_eq(ret, 1);
> +                igt_assert(pollfd.revents & POLLIN);
> +
> +                while ((ret = read(stream_fd, buf, sizeof(buf))) < 0 &&
> +                       errno == EINTR)
> +                        ;
> +
> +                /* Don't expect to see EAGAIN if we've had a POLLIN event
> +                 *
> +                 * XXX: actually this is technically overly strict since we do
> +                 * knowingly allow false positive POLLIN events. At least in
> +                 * the future when supporting context filtering of metrics for
> +                 * Gen8+ handled in the kernel then POLLIN events may be
> +                 * delivered when we know there are pending reports to process
> +                 * but before we've done any filtering to know for certain that
> +                 * any reports are destined to be copied to userspace.
> +                 *
> +                 * Still, for now it's a reasonable sanity check.
> +                 */
> +                if (ret < 0)
> +                        igt_debug("Unexpected error when reading after poll = %d\n", errno);
> +                igt_assert_neq(ret, -1);
> +
> +                /* At this point, after consuming pending reports (and hoping
> +                 * the scheduler hasn't stopped us for too long we now
> +                 * expect EAGAIN on read.
> +                 */
> +                while ((ret = read(stream_fd, buf, sizeof(buf))) < 0 &&
> +                       errno == EINTR)
> +                        ;
> +                igt_assert_eq(ret, -1);
> +                igt_assert_eq(errno, EAGAIN);
> +
> +                n++;
> +        }
> +
> +        times(&end_times);
> +
> +        /* Using nanosecond units is fairly silly here, given the tick in-
> +         * precision - ah well, it's consistent with the get_time() units.
> +         */
> +        user_ns = (end_times.tms_utime - start_times.tms_utime) * tick_ns;
> +        kernel_ns = (end_times.tms_stime - start_times.tms_stime) * tick_ns;
> +
> +        igt_debug("%d blocking poll()s in 600 milliseconds, with 25Hz OA sampling\n", n);
> +        igt_debug("time in userspace = %"PRIu64"ns (start utime = %d, end = %d, ns ticks per sec = %d)\n",
> +                  user_ns, (int)start_times.tms_utime, (int)end_times.tms_utime, (int)tick_ns);
> +        igt_debug("time in kernelspace = %"PRIu64"ns (start stime = %d, end = %d, ns ticks per sec = %d)\n",
> +                  kernel_ns, (int)start_times.tms_stime, (int)end_times.tms_stime, (int)tick_ns);
> +
> +        /* With completely broken blocking while polling (but still somehow
> +         * reporting a POLLIN event) we could end up with an open loop,
> +         * hopefully recognisable with > 15 (600/40)iterations.
> +         */
> +        igt_assert(n <= 15);
> +
> +        /* It's a bit tricky to put a lower limit here, but we expect a
> +         * relatively low latency for seeing reports, while we don't currently
> +         * give any control over this in the api.
> +         *
> +         * Limited to a 5 millisecond latency and 45ms (worst case)
> +         * per-iteration that could give 13.3 iterations. Rounding gives a tiny
> +         * bit more latency slack (6ms)...
> +         */
> +        igt_assert(n > 13);
> +
> +        /* A bit tricky to put a number on this, but we don't expect the kernel
> +         * to use any significant cpu while waiting and given the in precision
> +         * of stime (multiple of CLK_TCK) we expect this to round to zero.
> +         */
> +        igt_assert_eq(kernel_ns, 0);
> +
> +        close(stream_fd);
> +}
> +
> +static void
> +test_buffer_fill(void)
> +{
> +        int oa_exponent = 5; /* 5 micro seconds */
> +        uint64_t properties[] = {
> +                /* Include OA reports in samples */
> +                DRM_I915_PERF_PROP_SAMPLE_OA, true,
> +
> +                /* OA unit configuration */
> +                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
> +                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
> +                DRM_I915_PERF_PROP_OA_EXPONENT, oa_exponent,
> +        };
> +        struct drm_i915_perf_open_param param = {
> +                .flags = I915_PERF_FLAG_FD_CLOEXEC,
> +                .num_properties = sizeof(properties) / 16,
> +                .properties_ptr = (uint64_t)properties,
> +        };
> +        int stream_fd = __perf_open(drm_fd, &param);
> +        int buf_size = 65536 * (256 + sizeof(struct drm_i915_perf_record_header));
> +        uint8_t *buf = malloc(buf_size);
> +
> +
> +        for (int i = 0; i < 5; i++) {
> +                struct drm_i915_perf_record_header *header;
> +                bool overflow_seen;
> +                int offset = 0;
> +                int len;
> +
> +                /* It should take ~330 milliseconds to fill a 16MB OA buffer with a
> +                 * 5 microsecond sampling period and 256 byte reports. */
> +                nanosleep(&(struct timespec){ .tv_sec = 0, .tv_nsec = 500000000 }, NULL);
> +
> +                while ((len = read(stream_fd, buf, buf_size)) == -1 && errno == EINTR)
> +                        ;
> +
> +                igt_assert_neq(len, -1);
> +
> +                overflow_seen = false;
> +                for (offset = 0; offset < len; offset += header->size) {
> +                        header = (void *)(buf + offset);
> +
> +                        if (header->type == DRM_I915_PERF_RECORD_OA_BUFFER_LOST)
> +                                overflow_seen = true;
> +                }
> +
> +                igt_assert_eq(overflow_seen, true);
> +
> +                nanosleep(&(struct timespec){ .tv_sec = 0, .tv_nsec = 1000000 }, NULL);
> +
> +                while ((len = read(stream_fd, buf, buf_size)) == -1 && errno == EINTR)
> +                        ;
> +
> +                igt_assert_neq(len, -1);
> +
> +                /* expect ~ 200 records in 1 millisecond */
> +                igt_assert(len > 256 * 150);
> +
> +                overflow_seen = false;
> +                for (offset = 0; offset < len; offset += header->size) {
> +                        header = (void *)(buf + offset);
> +
> +                        if (header->type == DRM_I915_PERF_RECORD_OA_BUFFER_LOST)
> +                                overflow_seen = true;
> +                }
> +
> +                igt_assert_eq(overflow_seen, false);
> +        }
> +
> +        free(buf);
> +
> +        close(stream_fd);
> +}
> +
> +static void
> +test_enable_disable(void)
> +{
> +        int oa_exponent = 5; /* 5 micro seconds */
> +        uint64_t properties[] = {
> +                /* Include OA reports in samples */
> +                DRM_I915_PERF_PROP_SAMPLE_OA, true,
> +
> +                /* OA unit configuration */
> +                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
> +                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
> +                DRM_I915_PERF_PROP_OA_EXPONENT, oa_exponent,
> +        };
> +        struct drm_i915_perf_open_param param = {
> +                .flags = I915_PERF_FLAG_FD_CLOEXEC |
> +                         I915_PERF_FLAG_DISABLED, /* Verify we start disabled */
> +                .num_properties = sizeof(properties) / 16,
> +                .properties_ptr = (uint64_t)properties,
> +        };
> +        int stream_fd = __perf_open(drm_fd, &param);
> +        int buf_size = 65536 * (256 + sizeof(struct drm_i915_perf_record_header));
> +        uint8_t *buf = malloc(buf_size);
> +
> +
> +        for (int i = 0; i < 5; i++) {
> +                int len;
> +
> +                /* If the stream were enabled then it would take ~330
> +                 * milliseconds to fill a 16MB OA buffer with a 5 microsecond
> +                 * sampling period and 256 byte reports.
> +                 *
> +                 * Giving enough time for an overflow might help catch whether
> +                 * the OA unit has been enabled even if the driver might at
> +                 * least avoid copying reports while disabled.
> +                 */
> +                nanosleep(&(struct timespec){ .tv_sec = 0, .tv_nsec = 500000000 }, NULL);
> +
> +                while ((len = read(stream_fd, buf, buf_size)) == -1 && errno == EINTR)
> +                        ;
> +
> +                igt_assert_eq(len, -1);
> +                igt_assert_eq(errno, EIO);
> +
> +                do_ioctl(stream_fd, I915_PERF_IOCTL_ENABLE, 0);
> +
> +                nanosleep(&(struct timespec){ .tv_sec = 0, .tv_nsec = 1000000 }, NULL);
> +
> +                while ((len = read(stream_fd, buf, buf_size)) == -1 && errno == EINTR)
> +                        ;
> +
> +                igt_assert_neq(len, -1);
> +
> +                /* expect ~ 200 records in 1 millisecond */
> +                igt_assert(len > 256 * 150 && len < 256 * 2000);
> +
> +                do_ioctl(stream_fd, I915_PERF_IOCTL_DISABLE, 0);
> +
> +                /* It's considered an error to read a stream while it's disabled
> +                 * since it would block indefinitely...
> +                 */
> +                len = read(stream_fd, buf, buf_size);
> +
> +                igt_assert_eq(len, -1);
> +                igt_assert_eq(errno, EIO);
> +        }
> +
> +        free(buf);
> +
> +        close(stream_fd);
> +}
> +
> +static void
> +test_short_reads(void)
> +{
> +        int oa_exponent = 5; /* 5 micro seconds */
> +        uint64_t properties[] = {
> +                /* Include OA reports in samples */
> +                DRM_I915_PERF_PROP_SAMPLE_OA, true,
> +
> +                /* OA unit configuration */
> +                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
> +                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
> +                DRM_I915_PERF_PROP_OA_EXPONENT, oa_exponent,
> +        };
> +        struct drm_i915_perf_open_param param = {
> +                .flags = I915_PERF_FLAG_FD_CLOEXEC,
> +                .num_properties = sizeof(properties) / 16,
> +                .properties_ptr = (uint64_t)properties,
> +        };
> +        size_t record_size = 256 + sizeof(struct drm_i915_perf_record_header);
> +        size_t page_size = sysconf(_SC_PAGE_SIZE);
> +        int zero_fd = open("/dev/zero", O_RDWR|O_CLOEXEC);
> +        uint8_t *pages = mmap(NULL, page_size * 2,
> +                              PROT_READ|PROT_WRITE, MAP_PRIVATE, zero_fd, 0);
I don't see an munmap or close(zero_fd) anywhere ?

> +        struct drm_i915_perf_record_header *header;
> +        int stream_fd;
> +        int ret;
> +
> +        igt_assert(pages);
> +
> +        ret = mprotect(pages + page_size, page_size, PROT_NONE);
> +        igt_assert_eq(ret, 0);
> +
> +        stream_fd = __perf_open(drm_fd, &param);
> +
> +        nanosleep(&(struct timespec){ .tv_sec = 0, .tv_nsec = 5000000 }, NULL);
> +
> +        /* At this point there should be lots of pending reports to read */
> +
> +        /* A read that can return at least one record should result in a short
> +         * read not an EFAULT if the buffer is smaller than the requested read
> +         * size...
> +         *
> +         * Expect to see a sample record here, but at least skip over any
> +         * _RECORD_LOST notifications.
> +         */
> +        do {
> +                header = (void *)(pages + page_size - record_size);
> +                ret = read(stream_fd,
> +                           header,
> +                           page_size);
> +                igt_assert(ret > 0);
> +        } while (header->type == DRM_I915_PERF_RECORD_OA_REPORT_LOST);
> +
> +        igt_assert_eq(ret, record_size);
> +
> +        /* A read that can't return a single record because it would result
> +         * in a fault on buffer overrun should result in an EFAULT error...
> +         */
> +        ret = read(stream_fd, pages + page_size - 16, page_size);
> +        igt_assert_eq(ret, -1);
> +        igt_assert_eq(errno, EFAULT);
> +
> +        /* A read that can't return a single record because the buffer is too
> +         * small should result in an ENOSPC error..
> +         *
> +         * Again, skip over _RECORD_LOST records (smaller than record_size/2)
> +         */
> +        do {
> +                header = (void *)(pages + page_size - record_size / 2);
> +                ret = read(stream_fd,
> +                           header,
> +                           record_size / 2);
> +        } while (ret > 0 && header->type == DRM_I915_PERF_RECORD_OA_REPORT_LOST);
> +
> +        igt_assert_eq(ret, -1);
> +        igt_assert_eq(errno, ENOSPC);
> +
> +        close(stream_fd);
> +}
> +
> +static void
> +test_non_sampling_read_error(void)
> +{
> +        uint64_t properties[] = {
> +                /* XXX: even without periodic sampling we have to
> +                 * specify at least one sample layout property...
> +                 */
> +                DRM_I915_PERF_PROP_SAMPLE_OA, true,
> +
> +                /* OA unit configuration */
> +                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
> +                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
> +
> +                /* XXX: no sampling exponent */
> +        };
> +        struct drm_i915_perf_open_param param = {
> +                .flags = I915_PERF_FLAG_FD_CLOEXEC,
> +                .num_properties = sizeof(properties) / 16,
> +                .properties_ptr = (uint64_t)properties,
> +        };
> +        int stream_fd = __perf_open(drm_fd, &param);
> +        uint8_t buf[1024];
> +
> +        int ret = read(stream_fd, buf, sizeof(buf));
> +        igt_assert_eq(ret, -1);
> +        igt_assert_eq(errno, EIO);
> +
> +        close(stream_fd);
> +}
> +
> +/* Check that attempts to read from a stream while it is disable will return
> + * EIO instead of blocking indefinitely.
> + */
> +static void
> +test_disabled_read_error(void)
> +{
> +        int oa_exponent = 5; /* 5 micro seconds */
> +        uint64_t properties[] = {
> +                /* XXX: even without periodic sampling we have to
> +                 * specify at least one sample layout property...
> +                 */
> +                DRM_I915_PERF_PROP_SAMPLE_OA, true,
> +
> +                /* OA unit configuration */
> +                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
> +                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
> +                DRM_I915_PERF_PROP_OA_EXPONENT, oa_exponent,
> +        };
> +        struct drm_i915_perf_open_param param = {
> +                .flags = I915_PERF_FLAG_FD_CLOEXEC |
> +                         I915_PERF_FLAG_DISABLED, /* XXX: open disabled */
> +                .num_properties = sizeof(properties) / 16,
> +                .properties_ptr = (uint64_t)properties,
> +        };
> +        int stream_fd = __perf_open(drm_fd, &param);
> +        uint32_t oa_report0[64];
> +        uint32_t oa_report1[64];
> +        uint32_t buf[128] = { 0 };
> +        int ret;
> +
> +
> +        ret = read(stream_fd, buf, sizeof(buf));
> +        igt_assert_eq(ret, -1);
> +        igt_assert_eq(errno, EIO);
> +
> +        close(stream_fd);
> +
> +
> +        param.flags &= ~I915_PERF_FLAG_DISABLED;
> +        stream_fd = __perf_open(drm_fd, &param);
> +
> +        read_2_oa_reports(stream_fd,
> +                          I915_OA_FORMAT_A45_B8_C8, 256,
> +                          oa_exponent,
> +                          oa_report0,
> +                          oa_report1,
> +                          false); /* not just timer reports */
> +
> +        do_ioctl(stream_fd, I915_PERF_IOCTL_DISABLE, 0);
> +
> +        ret = read(stream_fd, buf, sizeof(buf));
> +        igt_assert_eq(ret, -1);
> +        igt_assert_eq(errno, EIO);
> +
> +        do_ioctl(stream_fd, I915_PERF_IOCTL_ENABLE, 0);
> +
> +        read_2_oa_reports(stream_fd,
> +                          I915_OA_FORMAT_A45_B8_C8, 256,
> +                          oa_exponent,
> +                          oa_report0,
> +                          oa_report1,
> +                          false); /* not just timer reports */
> +
> +        close(stream_fd);
> +}
> +
> +static void
> +test_mi_rpc(void)
> +{
> +        uint64_t properties[] = {
> +                /* Note: we have to specify at least one sample property even
> +                 * though we aren't interested in samples in this case.
> +                 */
> +                DRM_I915_PERF_PROP_SAMPLE_OA, true,
> +
> +                /* OA unit configuration */
> +                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
> +                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
> +
> +                /* Note: no OA exponent specified in this case */
> +        };
> +        struct drm_i915_perf_open_param param = {
> +                .flags = I915_PERF_FLAG_FD_CLOEXEC,
> +                .num_properties = sizeof(properties) / 16,
> +                .properties_ptr = (uint64_t)properties,
> +        };
> +        int stream_fd = __perf_open(drm_fd, &param);
> +        drm_intel_bufmgr *bufmgr = drm_intel_bufmgr_gem_init(drm_fd, 4096);
> +        drm_intel_context *context;
> +        struct intel_batchbuffer *batch;
> +        drm_intel_bo *bo;
> +        uint32_t *report32;
> +        int ret;
> +
> +        drm_intel_bufmgr_gem_enable_reuse(bufmgr);
> +
> +        context = drm_intel_gem_context_create(bufmgr);
> +        igt_assert(context);
> +
> +        batch = intel_batchbuffer_alloc(bufmgr, devid);
> +
> +        bo = drm_intel_bo_alloc(bufmgr, "mi_rpc dest bo", 4096, 64);
> +
> +        ret = drm_intel_bo_map(bo, true);
> +        igt_assert_eq(ret, 0);
> +
> +        memset(bo->virtual, 0x80, 4096);
> +        drm_intel_bo_unmap(bo);
> +
> +        BEGIN_BATCH(3, 1);
> +        OUT_BATCH(GEN6_MI_REPORT_PERF_COUNT);
> +        OUT_RELOC(bo, I915_GEM_DOMAIN_INSTRUCTION, I915_GEM_DOMAIN_INSTRUCTION,
> +                  0); /* offset in bytes */
> +        OUT_BATCH(0xdeadbeef); /* report ID */
> +        ADVANCE_BATCH();
> +
> +        intel_batchbuffer_flush_with_context(batch, context);
> +
> +        ret = drm_intel_bo_map(bo, false /* write enable */);
> +        igt_assert_eq(ret, 0);
> +
> +        report32 = bo->virtual;
> +        igt_assert_eq(report32[0], 0xdeadbeef); /* report ID */
> +        igt_assert_neq(report32[1], 0); /* timestamp */
> +
> +        igt_assert_neq(report32[63], 0x80808080); /* end of report */
> +        igt_assert_eq(report32[64], 0x80808080); /* after 256 byte report */
Missing a drm_intel_bo_unmap somewhere.

> +
> +        intel_batchbuffer_free(batch);
> +        drm_intel_gem_context_destroy(context);
> +        drm_intel_bufmgr_destroy(bufmgr);
> +        close(stream_fd);
> +}
> +
> +static void
> +scratch_buf_init(drm_intel_bufmgr *bufmgr,
> +                 struct igt_buf *buf,
> +                 int width, int height,
> +                 uint32_t color)
> +{
> +        size_t stride = width * 4;
> +        size_t size = stride * height;
> +	drm_intel_bo *bo = drm_intel_bo_alloc(bufmgr, "", size, 4096);
> +        int ret;
> +
> +        ret = drm_intel_bo_map(bo, true /* writable */);
> +        igt_assert_eq(ret, 0);
> +
> +        for (int i = 0; i < width * height; i++)
> +                ((uint32_t *)bo->virtual)[i] = color;
> +
> +        drm_intel_bo_unmap(bo);
> +
> +	buf->bo = bo;
> +	buf->stride = stride;
> +	buf->tiling = I915_TILING_NONE;
> +	buf->size = size;
> +}
The whitespace formatting here is pretty sketchy.

> +
> +static void
> +emit_stall_timestamp_and_rpc(struct intel_batchbuffer *batch,
> +                             drm_intel_bo *dst,
> +                             int timestamp_offset,
> +                             int report_dst_offset,
> +                             uint32_t report_id)
> +{
> +        uint32_t pipe_ctl_flags = (PIPE_CONTROL_CS_STALL |
> +                                   PIPE_CONTROL_RENDER_TARGET_FLUSH |
> +                                   PIPE_CONTROL_WRITE_TIMESTAMP);
> +
> +        BEGIN_BATCH(5, 1);
> +        OUT_BATCH(GFX_OP_PIPE_CONTROL | (5 - 2));
> +        OUT_BATCH(pipe_ctl_flags);
> +        OUT_RELOC(dst, I915_GEM_DOMAIN_INSTRUCTION, I915_GEM_DOMAIN_INSTRUCTION,
> +                  timestamp_offset);
> +        OUT_BATCH(0); /* imm lower */
> +        OUT_BATCH(0); /* imm upper */
> +        ADVANCE_BATCH();
> +
> +        BEGIN_BATCH(3, 1);
> +        OUT_BATCH(GEN6_MI_REPORT_PERF_COUNT);
> +        OUT_RELOC(dst, I915_GEM_DOMAIN_INSTRUCTION, I915_GEM_DOMAIN_INSTRUCTION,
> +                  report_dst_offset);
> +        OUT_BATCH(report_id);
> +        ADVANCE_BATCH();
> +}
> +
> +/* Tests the INTEL_performance_query use case where an unprivileged process
> + * should be able to configure the OA unit for per-context metrics (for a
> + * context associated with that process' drm file descriptor) and the counters
> + * should only relate to that specific context.
> + */
> +static void
> +test_per_ctx_mi_rpc(void)
> +{
> +        uint64_t properties[] = {
> +                DRM_I915_PERF_PROP_CTX_HANDLE, UINT64_MAX, /* updated below */
> +
> +                /* Note: we have to specify at least one sample property even
> +                 * though we aren't interested in samples in this case
> +                 */
> +                DRM_I915_PERF_PROP_SAMPLE_OA, true,
> +
> +                /* OA unit configuration */
> +                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
> +                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
> +
> +                /* Note: no OA exponent specified in this case */
> +        };
> +        struct drm_i915_perf_open_param param = {
> +                .flags = I915_PERF_FLAG_FD_CLOEXEC,
> +                .num_properties = sizeof(properties) / 16,
> +                .properties_ptr = (uint64_t)properties,
> +        };
> +
> +        /* should be default, but just to be sure... */
> +        write_u64_file("/proc/sys/dev/i915/perf_stream_paranoid", 1);
> +
> +        igt_fork(child, 1) {
> +                drm_intel_bufmgr *bufmgr;
> +                drm_intel_context *context0, *context1;
> +                int stream_fd;
> +                struct intel_batchbuffer *batch;
> +                struct igt_buf src, dst;
> +                drm_intel_bo *bo;
> +                uint32_t *report0_32, *report1_32;
> +                uint64_t timestamp0_64, timestamp1_64;
> +                uint32_t delta_ts64, delta_oa32;
> +                uint64_t delta_ts64_ns, delta_oa32_ns;
> +                uint32_t delta_delta;
> +                int n_samples_written;
> +                int width = 800;
> +                int height = 600;
> +                int ret;
> +
> +                igt_drop_root();
> +
> +                bufmgr = drm_intel_bufmgr_gem_init(drm_fd, 4096);
> +                drm_intel_bufmgr_gem_enable_reuse(bufmgr);
> +
> +                scratch_buf_init(bufmgr, &src, width, height, 0xff0000ff);
> +                scratch_buf_init(bufmgr, &dst, width, height, 0x00ff00ff);
> +
> +                batch = intel_batchbuffer_alloc(bufmgr, devid);
> +
> +                context0 = drm_intel_gem_context_create(bufmgr);
> +                igt_assert(context0);
> +
> +                context1 = drm_intel_gem_context_create(bufmgr);
> +                igt_assert(context1);
> +
> +                igt_debug("submitting warm up render_copy\n");
> +
> +                /* Submit some early, unmeasured, work to the context we want
> +                 * to measure to try and catch issues with i915-perf
> +                 * initializing the HW context ID for filtering.
> +                 *
> +                 * We do this because i915-perf single context filtering had
> +                 * previously only relied on a hook into context pinning to
> +                 * initialize the HW context ID, instead of also trying to
> +                 * determine the HW ID while opening the stream, in case it
> +                 * has already been pinned.
> +                 *
> +                 * This wasn't noticed by the previous unit test because we
> +                 * were opening the stream while the context hadn't been
> +                 * touched or pinned yet and so it worked out correctly to wait
> +                 * for the pinning hook.
> +                 *
> +                 * Now a buggy version of i915-perf will fail to measure
> +                 * anything for context0 once this initial render_copy() ends
> +                 * up pinning the context since there won't ever be a pinning
> +                 * hook callback.
> +                 */
> +                render_copy(batch,
> +                            context0,
> +                            &src, 0, 0, width, height,
> +                            &dst, 0, 0);
> +
> +                properties[1] = drm_intel_gem_context_get_context_id(context0);
> +
> +                igt_debug("opening i915-perf stream\n");
> +                stream_fd = __perf_open(drm_fd, &param);
> +
> +                bo = drm_intel_bo_alloc(bufmgr, "mi_rpc dest bo", 4096, 64);
> +
> +                ret = drm_intel_bo_map(bo, true /* write enable */);
> +                igt_assert_eq(ret, 0);
> +
> +                memset(bo->virtual, 0x80, 4096);
> +                drm_intel_bo_unmap(bo);
> +
> +                emit_stall_timestamp_and_rpc(batch,
> +                                             bo,
> +                                             512 /* timestamp offset */,
> +                                             0, /* report dst offset */
> +                                             0xdeadbeef); /* report id */
> +
> +                /* Explicitly flush here (even though the render_copy() call
> +                 * will itself flush before/after the copy) to clarify that
> +                 * that the PIPE_CONTROL + MI_RPC commands will be in a
> +                 * separate batch from the copy.
> +                 */
> +                intel_batchbuffer_flush_with_context(batch, context0);
> +
> +                render_copy(batch,
> +                            context0,
> +                            &src, 0, 0, width, height,
> +                            &dst, 0, 0);
> +
> +                /* Another redundant flush to clarify batch bo is free to reuse */
> +                intel_batchbuffer_flush_with_context(batch, context0);
> +
> +                /* submit two copies on the other context to avoid a false
> +                 * positive in case the driver somehow ended up filtering for
> +                 * context1
> +                 */
> +                render_copy(batch,
> +                            context1,
> +                            &src, 0, 0, width, height,
> +                            &dst, 0, 0);
> +
> +                render_copy(batch,
> +                            context1,
> +                            &src, 0, 0, width, height,
> +                            &dst, 0, 0);
> +
> +                /* And another */
> +                intel_batchbuffer_flush_with_context(batch, context1);
> +
> +                emit_stall_timestamp_and_rpc(batch,
> +                                             bo,
> +                                             520 /* timestamp offset */,
> +                                             256, /* report dst offset */
> +                                             0xbeefbeef); /* report id */
> +
> +                intel_batchbuffer_flush_with_context(batch, context0);
> +
> +                ret = drm_intel_bo_map(bo, false /* write enable */);
> +                igt_assert_eq(ret, 0);
> +
> +                report0_32 = bo->virtual;
> +                igt_assert_eq(report0_32[0], 0xdeadbeef); /* report ID */
> +                igt_assert_neq(report0_32[1], 0); /* timestamp */
> +
> +                report1_32 = report0_32 + 64;
> +                igt_assert_eq(report1_32[0], 0xbeefbeef); /* report ID */
> +                igt_assert_neq(report1_32[1], 0); /* timestamp */
> +
> +                print_reports(report0_32, report1_32,
> +                              lookup_format(I915_OA_FORMAT_A45_B8_C8));
> +
> +                /* A40 == N samples written to all render targets */
> +                n_samples_written = report1_32[43] - report0_32[43];
> +                igt_debug("n samples written = %d\n", n_samples_written);
> +                igt_assert_eq(n_samples_written, width * height);
> +
> +                igt_debug("timestamp32 0 = %u\n", report0_32[1]);
> +                igt_debug("timestamp32 1 = %u\n", report1_32[1]);
> +
> +                timestamp0_64 = *(uint64_t *)(((uint8_t *)bo->virtual) + 512);
> +                timestamp1_64 = *(uint64_t *)(((uint8_t *)bo->virtual) + 520);
> +
> +                igt_debug("timestamp64 0 = %"PRIu64"\n", timestamp0_64);
> +                igt_debug("timestamp64 1 = %"PRIu64"\n", timestamp1_64);
> +
> +                delta_ts64 = timestamp1_64 - timestamp0_64;
> +                delta_oa32 = report1_32[1] - report0_32[1];
> +
> +                /* sanity check that we can pass the delta to timebase_scale */
> +                igt_assert(delta_ts64 < UINT32_MAX);
> +                delta_oa32_ns = timebase_scale(delta_oa32);
> +                delta_ts64_ns = timebase_scale(delta_ts64);
> +
> +                igt_debug("ts32 delta = %u, = %uns\n",
> +                          delta_oa32, (unsigned)delta_oa32_ns);
> +                igt_debug("ts64 delta = %u, = %uns\n",
> +                          delta_ts64, (unsigned)delta_ts64_ns);
> +
> +                /* The delta as calculated via the PIPE_CONTROL timestamp or
> +                 * the OA report timestamps should be almost identical but
> +                 * allow a 320 nanoseconds margin.
> +                 */
> +                delta_delta = delta_ts64_ns > delta_oa32_ns ?
> +                        (delta_ts64_ns - delta_oa32_ns) :
> +                        (delta_oa32_ns - delta_ts64_ns);
> +                igt_assert(delta_delta <= 320);
> +
Missing a drm_intel_bo_unmap somewhere.

> +                intel_batchbuffer_free(batch);
> +                drm_intel_gem_context_destroy(context0);
> +                drm_intel_gem_context_destroy(context1);
> +                drm_intel_bufmgr_destroy(bufmgr);
> +                close(stream_fd);
> +        }
> +
> +        igt_waitchildren();
> +}
> +
> +static void
> +test_rc6_disable(void)
> +{
> +        int oa_exponent = 13; /* 1 millisecond */
> +        uint64_t properties[] = {
> +                /* Include OA reports in samples */
> +                DRM_I915_PERF_PROP_SAMPLE_OA, true,
> +
> +                /* OA unit configuration */
> +                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
> +                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
> +                DRM_I915_PERF_PROP_OA_EXPONENT, oa_exponent,
> +        };
> +        struct drm_i915_perf_open_param param = {
> +                .flags = I915_PERF_FLAG_FD_CLOEXEC,
> +                .num_properties = sizeof(properties) / 16,
> +                .properties_ptr = (uint64_t)properties,
> +        };
> +        int stream_fd = __perf_open(drm_fd, &param);
> +        uint64_t n_events_start = read_debugfs_u64_record("i915_drpc_info",
> +                                                          "RC6 residency since boot");
> +        uint64_t n_events_end;
> +
> +        nanosleep(&(struct timespec){ .tv_sec = 0, .tv_nsec = 500000000 }, NULL);
> +
> +        n_events_end = read_debugfs_u64_record("i915_drpc_info",
> +                                               "RC6 residency since boot");
> +
> +        igt_assert_eq(n_events_end - n_events_start, 0);
> +
> +        close(stream_fd);
> +
> +        n_events_start = read_debugfs_u64_record("i915_drpc_info",
> +                                                 "RC6 residency since boot");
> +
> +        nanosleep(&(struct timespec){ .tv_sec = 0, .tv_nsec = 500000000 }, NULL);
> +
> +        n_events_end = read_debugfs_u64_record("i915_drpc_info",
> +                                               "RC6 residency since boot");
> +
> +        igt_assert_neq(n_events_end - n_events_start, 0);
> +}
> +
> +static unsigned
> +read_i915_module_ref(void)
> +{
> +        FILE *fp = fopen("/proc/modules", "r");
> +        char *line = NULL;
> +        size_t line_buf_size = 0;
> +        int len = 0;
> +        unsigned ref_count;
> +
> +        igt_assert(fp);
> +
> +        while ((len = getline(&line, &line_buf_size, fp)) > 0) {
> +                if (strncmp(line, "i915 ", 5) == 0) {
> +                        unsigned long mem;
> +                        int ret = sscanf(line + 5, "%lu %u", &mem, &ref_count);
> +                        igt_assert(ret == 2);
> +                        goto done;
> +                }
> +        }
> +
> +        igt_assert(!"reached");
> +
> +done:
> +        free(line);
> +        fclose(fp);
> +        return ref_count;
> +}
> +
> +/* check that an open i915 perf stream holds a reference on the drm i915 module
> + * including in the corner case where the original drm fd has been closed.
> + */
> +static void
> +test_i915_ref_count(void)
> +{
> +        int oa_exponent = 13; /* 1 millisecond */
> +        uint64_t properties[] = {
> +                /* Include OA reports in samples */
> +                DRM_I915_PERF_PROP_SAMPLE_OA, true,
> +
> +                /* OA unit configuration */
> +                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
> +                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
> +                DRM_I915_PERF_PROP_OA_EXPONENT, oa_exponent,
> +        };
> +        struct drm_i915_perf_open_param param = {
> +                .flags = I915_PERF_FLAG_FD_CLOEXEC,
> +                .num_properties = sizeof(properties) / 16,
> +                .properties_ptr = (uint64_t)properties,
> +        };
> +        unsigned baseline, ref_count0, ref_count1;
> +        int stream_fd;
> +        uint32_t oa_report0[64];
> +        uint32_t oa_report1[64];
> +
> +        close(drm_fd);
> +        baseline = read_i915_module_ref();
> +        igt_debug("baseline ref count (drm fd closed) = %u\n", baseline);
> +
> +        drm_fd = drm_open_driver_render(DRIVER_INTEL);
> +        ref_count0 = read_i915_module_ref();
> +        igt_debug("initial ref count with drm_fd open = %u\n", ref_count0);
> +        igt_assert(ref_count0 > baseline);
> +
> +        stream_fd = __perf_open(drm_fd, &param);
> +        ref_count1 = read_i915_module_ref();
> +        igt_debug("ref count after opening i915 perf stream = %u\n", ref_count1);
> +        igt_assert(ref_count1 > ref_count0);
> +
> +        close(drm_fd);
> +        ref_count0 = read_i915_module_ref();
> +        igt_debug("ref count after closing drm fd = %u\n", ref_count0);
> +
> +        igt_assert(ref_count0 > baseline);
> +
> +        read_2_oa_reports(stream_fd,
> +                          I915_OA_FORMAT_A45_B8_C8, 256,
> +                          oa_exponent,
> +                          oa_report0,
> +                          oa_report1,
> +                          false); /* not just timer reports */
> +
> +        close(stream_fd);
> +        ref_count0 = read_i915_module_ref();
> +        igt_debug("ref count after closing i915 perf stream fd = %u\n", ref_count0);
> +        igt_assert_eq(ref_count0, baseline);
> +
> +        drm_fd = drm_open_driver_render(DRIVER_INTEL);
> +}
> +
> +igt_main
> +{
> +        igt_skip_on_simulation();
> +
> +        igt_fixture {
> +                struct stat sb;
> +                int ret;
> +
> +                drm_fd = drm_open_driver_render(DRIVER_INTEL);
> +                devid = intel_get_drm_devid(drm_fd);
> +                device = drm_get_card();
> +
> +                igt_require(IS_HASWELL(devid));
> +                igt_require(lookup_hsw_render_basic_id());
> +
> +                ret = stat("/proc/sys/dev/i915/perf_stream_paranoid", &sb);
> +                igt_require(ret == 0);
> +                ret = stat("/proc/sys/dev/i915/oa_max_sample_rate", &sb);
> +                igt_require(ret == 0);
The absence of the above files would indicate a failure in the kernel,
so would it not be more apt to assert, rather than skip ?

> +
> +                gt_frequency_range_save();
> +
> +                write_u64_file("/proc/sys/dev/i915/perf_stream_paranoid", 1);
Don't we also want to ensure that the oa_max_sample_rate is also in a
"good" starting state before we begin, especially since we ensure that
we leave in its default state when cleaning up ?

Anyway, I think it all looks pretty reasonable to me and it looks like
we have a good amount of coverage, so you can have my r-b with Chris'
comment addressed.

> +
> +                render_copy = igt_get_render_copyfunc(devid);
> +                igt_require_f(render_copy, "no render-copy function\n");
> +        }
> +
> +        igt_subtest("non-system-wide-paranoid")
> +                test_system_wide_paranoid();
> +
> +        igt_subtest("invalid-open-flags")
> +                test_invalid_open_flags();
> +
> +        igt_subtest("invalid-oa-metric-set-id")
> +                test_invalid_oa_metric_set_id();
> +
> +        igt_subtest("invalid-oa-format-id")
> +                test_invalid_oa_format_id();
> +
> +        igt_subtest("missing-sample-flags")
> +                test_missing_sample_flags();
> +
> +        igt_subtest("oa-formats")
> +                test_oa_formats();
> +
> +        igt_subtest("invalid-oa-exponent")
> +                test_invalid_oa_exponent();
> +        igt_subtest("low-oa-exponent-permissions")
> +                test_low_oa_exponent_permissions();
> +        igt_subtest("oa-exponents") {
> +                test_oa_exponents(450);
> +                test_oa_exponents(550);
> +        }
> +
> +        igt_subtest("per-context-mode-unprivileged")
> +                test_per_context_mode_unprivileged();
> +
> +        igt_subtest("buffer-fill")
> +                test_buffer_fill();
> +
> +        igt_subtest("disabled-read-error")
> +                test_disabled_read_error();
> +        igt_subtest("non-sampling-read-error")
> +                test_non_sampling_read_error();
> +
> +        igt_subtest("enable-disable")
> +                test_enable_disable();
> +
> +        igt_subtest("blocking")
> +                test_blocking();
> +
> +        igt_subtest("polling")
> +                test_polling();
> +
> +        igt_subtest("short-reads")
> +                test_short_reads();
> +
> +        igt_subtest("mi-rpc")
> +                test_mi_rpc();
> +
> +        igt_subtest("mi-rpc-per-ctx")
> +                test_per_ctx_mi_rpc();
> +
> +        igt_subtest("i915-ref-count")
> +                test_i915_ref_count();
> +
> +        igt_subtest("rc6-disable")
> +                test_rc6_disable();
> +
> +        igt_fixture {
> +                /* leave sysctl options in their default state... */
> +                write_u64_file("/proc/sys/dev/i915/oa_max_sample_rate", 100000);
> +                write_u64_file("/proc/sys/dev/i915/perf_stream_paranoid", 1);
> +
> +                gt_frequency_range_restore();
> +
> +                close(drm_fd);
> +        }
> +}
> -- 
> 2.10.1
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
Robert Bragg Nov. 14, 2016, 3:52 p.m. UTC | #3
On Thu, Nov 10, 2016 at 11:03 PM, Matthew Auld <matthew.william.auld@gmail.
com> wrote:

> On 11/09, Robert Bragg wrote:
> > +
> > +igt_main
> > +{
> > +        igt_skip_on_simulation();
> > +
> > +        igt_fixture {
> > +                struct stat sb;
> > +                int ret;
> > +
> > +                drm_fd = drm_open_driver_render(DRIVER_INTEL);
> > +                devid = intel_get_drm_devid(drm_fd);
> > +                device = drm_get_card();
> > +
> > +                igt_require(IS_HASWELL(devid));
> > +                igt_require(lookup_hsw_render_basic_id());
> > +
> > +                ret = stat("/proc/sys/dev/i915/perf_stream_paranoid",
> &sb);
> > +                igt_require(ret == 0);
> > +                ret = stat("/proc/sys/dev/i915/oa_max_sample_rate",
> &sb);
> > +                igt_require(ret == 0);
> The absence of the above files would indicate a failure in the kernel,
> so would it not be more apt to assert, rather than skip ?
>

The test could be running against an older kernel which won't have these
files and we should skip all the tests in that case.

E.g. Chris asked me to maintain compatibility within the gem_exec_parse
test for older versions of the command parser so I suppose i-g-t tries to
maintain backwards compatibility.

We could potentially require one and assert the other.


> > +
> > +                gt_frequency_range_save();
> > +
> > +                write_u64_file("/proc/sys/dev/i915/perf_stream_paranoid",
> 1);
> Don't we also want to ensure that the oa_max_sample_rate is also in a
> "good" starting state before we begin, especially since we ensure that
> we leave in its default state when cleaning up ?
>

Explicitly setting the max rate interferes with being able to assert what
the default is, but that's already a problem with the cleanup fixture
explicitly setting the rate.

What I'm doing now is initializing oa_max_sample_rate before tests, as
suggested here, and I've also added a test_sysctl_defaults() test that's
run very early, just after the i915-ref-count test.



>
> Anyway, I think it all looks pretty reasonable to me and it looks like
> we have a good amount of coverage, so you can have my r-b with Chris'
> comment addressed.
>

Thanks, I've moved the ref counting test in front of the first fixture as
suggested by chris (with just the requirements check that the i915-perf
interface exists in another fixture before).
diff mbox

Patch

diff --git a/tests/Makefile.sources b/tests/Makefile.sources
index 6d081c3..7c6de2f 100644
--- a/tests/Makefile.sources
+++ b/tests/Makefile.sources
@@ -211,6 +211,7 @@  TESTS_progs = \
 	kms_pwrite_crc \
 	kms_sink_crc_basic \
 	prime_udl \
+	perf \
 	$(NULL)
 
 # IMPORTANT: The ZZ_ tests need to be run last!
diff --git a/tests/perf.c b/tests/perf.c
new file mode 100644
index 0000000..4762e36
--- /dev/null
+++ b/tests/perf.c
@@ -0,0 +1,2220 @@ 
+/*
+ * Copyright © 2016 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <sys/times.h>
+#include <sys/types.h>
+#include <dirent.h>
+#include <time.h>
+#include <poll.h>
+#include <math.h>
+
+#include "igt.h"
+#include "drm.h"
+
+IGT_TEST_DESCRIPTION("Test the i915 perf metrics streaming interface");
+
+#define GEN6_MI_REPORT_PERF_COUNT ((0x28 << 23) | (3 - 2))
+
+#define GFX_OP_PIPE_CONTROL     ((3 << 29) | (3 << 27) | (2 << 24))
+#define PIPE_CONTROL_CS_STALL           (1 << 20)
+#define PIPE_CONTROL_GLOBAL_SNAPSHOT_COUNT_RESET        (1 << 19)
+#define PIPE_CONTROL_TLB_INVALIDATE     (1 << 18)
+#define PIPE_CONTROL_SYNC_GFDT          (1 << 17)
+#define PIPE_CONTROL_MEDIA_STATE_CLEAR  (1 << 16)
+#define PIPE_CONTROL_NO_WRITE           (0 << 14)
+#define PIPE_CONTROL_WRITE_IMMEDIATE    (1 << 14)
+#define PIPE_CONTROL_WRITE_DEPTH_COUNT  (2 << 14)
+#define PIPE_CONTROL_WRITE_TIMESTAMP    (3 << 14)
+#define PIPE_CONTROL_DEPTH_STALL        (1 << 13)
+#define PIPE_CONTROL_RENDER_TARGET_FLUSH (1 << 12)
+#define PIPE_CONTROL_INSTRUCTION_INVALIDATE (1 << 11)
+#define PIPE_CONTROL_TEXTURE_CACHE_INVALIDATE   (1 << 10) /* GM45+ only */
+#define PIPE_CONTROL_ISP_DIS            (1 << 9)
+#define PIPE_CONTROL_INTERRUPT_ENABLE   (1 << 8)
+#define PIPE_CONTROL_FLUSH_ENABLE       (1 << 7) /* Gen7+ only */
+/* GT */
+#define PIPE_CONTROL_DATA_CACHE_INVALIDATE      (1 << 5)
+#define PIPE_CONTROL_VF_CACHE_INVALIDATE        (1 << 4)
+#define PIPE_CONTROL_CONST_CACHE_INVALIDATE     (1 << 3)
+#define PIPE_CONTROL_STATE_CACHE_INVALIDATE     (1 << 2)
+#define PIPE_CONTROL_STALL_AT_SCOREBOARD        (1 << 1)
+#define PIPE_CONTROL_DEPTH_CACHE_FLUSH          (1 << 0)
+#define PIPE_CONTROL_PPGTT_WRITE        (0 << 2)
+#define PIPE_CONTROL_GLOBAL_GTT_WRITE   (1 << 2)
+
+#define NSEC_PER_SEC 1000000000ull
+
+static struct {
+        const char *name;
+        uint64_t id;
+        size_t size;
+        int a_off; /* bytes */
+        int n_a;
+        int first_a;
+        int b_off;
+        int n_b;
+        int c_off;
+        int n_c;
+} hsw_oa_formats[] = {
+        { "A13", I915_OA_FORMAT_A13, .size = 64,
+                .a_off = 12, .n_a = 13 },
+        { "A29", I915_OA_FORMAT_A29, .size = 128,
+                .a_off = 12, .n_a = 29 },
+        { "A13_B8_C8", I915_OA_FORMAT_A13_B8_C8, .size = 128,
+                .a_off = 12, .n_a = 13,
+                .b_off = 64, .n_b = 8,
+                .c_off = 96, .n_c = 8 },
+        { "A45_B8_C8", I915_OA_FORMAT_A45_B8_C8, .size = 256,
+                .a_off = 12,  .n_a = 45,
+                .b_off = 192, .n_b = 8,
+                .c_off = 224, .n_c = 8 },
+        { "B4_C8", I915_OA_FORMAT_B4_C8, .size = 64,
+                .b_off = 16, .n_b = 4,
+                .c_off = 32, .n_c = 8 },
+        { "B4_C8_A16", I915_OA_FORMAT_B4_C8_A16, .size = 128,
+                .b_off = 16, .n_b = 4,
+                .c_off = 32, .n_c = 8,
+                .a_off = 60, .n_a = 16, .first_a = 29 },
+        { "C4_B8", I915_OA_FORMAT_C4_B8, .size = 64,
+                .c_off = 16, .n_c = 4,
+                .b_off = 28, .n_b = 8 },
+};
+
+static bool hsw_undefined_a_counters[45] = {
+        [4] = true,
+        [6] = true,
+        [9] = true,
+        [11] = true,
+        [14] = true,
+        [16] = true,
+        [19] = true,
+        [21] = true,
+        [24] = true,
+        [26] = true,
+        [29] = true,
+        [31] = true,
+        [34] = true,
+        [43] = true,
+        [44] = true,
+};
+
+static int drm_fd;
+static uint32_t devid;
+static int device;
+
+static uint64_t hsw_render_basic_id = UINT64_MAX;
+static uint64_t gt_min_freq_mhz_saved = 0;
+static uint64_t gt_max_freq_mhz_saved = 0;
+static uint64_t gt_min_freq_mhz = 0;
+static uint64_t gt_max_freq_mhz = 0;
+
+static uint64_t timestamp_frequency = 12500000;
+
+static igt_render_copyfunc_t render_copy = NULL;
+
+static int
+__perf_open(int fd, struct drm_i915_perf_open_param *param)
+{
+        int ret = igt_ioctl(fd, DRM_IOCTL_I915_PERF_OPEN, param);
+
+        igt_assert(ret >= 0);
+        errno = 0;
+
+        return ret;
+}
+
+static int
+lookup_format(int i915_perf_fmt_id)
+{
+        for (int i = 0; i < ARRAY_SIZE(hsw_oa_formats); i++)
+                if (hsw_oa_formats[i].id == i915_perf_fmt_id)
+                        return i;
+
+        igt_assert(!"reached");
+}
+
+static bool
+try_read_u64_file(const char *file, uint64_t *val)
+{
+        char buf[32];
+        int fd, n;
+
+        fd = open(file, O_RDONLY);
+        if (fd < 0)
+                return false;
+
+        while ((n = read(fd, buf, sizeof(buf) - 1)) < 0 && errno == EINTR)
+                ;
+        igt_assert(n >= 0);
+
+        close(fd);
+
+        buf[n] = '\0';
+        *val = strtoull(buf, NULL, 0);
+
+        return true;
+}
+
+static uint64_t
+read_u64_file(const char *file)
+{
+        uint64_t val;
+
+        igt_assert_eq(try_read_u64_file(file, &val), true);
+
+        return val;
+}
+
+static void
+write_u64_file(const char *file, uint64_t val)
+{
+        char buf[32];
+        int fd, len, ret;
+
+        fd = open(file, O_WRONLY);
+        igt_assert(fd >= 0);
+
+        len = snprintf(buf, sizeof(buf), "%"PRIu64, val);
+        igt_assert(len > 0);
+
+        while ((ret = write(fd, buf, len)) < 0 && errno == EINTR)
+                ;
+        igt_assert_eq(ret, len);
+
+        close(fd);
+}
+
+static uint64_t
+sysfs_read(const char *file)
+{
+        char buf[512];
+
+        snprintf(buf, sizeof(buf), "/sys/class/drm/card%d/%s", device, file);
+
+        return read_u64_file(buf);
+}
+
+static void
+sysfs_write(const char *file, uint64_t val)
+{
+        char buf[512];
+
+        snprintf(buf, sizeof(buf), "/sys/class/drm/card%d/%s", device, file);
+
+        write_u64_file(buf, val);
+}
+
+static char *
+read_debugfs_record(const char *file, const char *key)
+{
+        FILE *fp;
+        char *line = NULL;
+        size_t line_buf_size = 0;
+        int len = 0;
+        int key_len = strlen(key);
+        char *value = NULL;
+
+        fp = igt_debugfs_fopen(file, "r");
+        igt_require(fp);
+
+        while ((len = getline(&line, &line_buf_size, fp)) > 0) {
+
+                if (line[len - 1] == '\n')
+                        line[len - 1] = '\0';
+
+                if (strncmp(key, line, key_len) == 0 &&
+                    line[key_len] == ':' &&
+                    line[key_len + 1] == ' ')
+                {
+                        value = strdup(line + key_len + 2);
+                        goto done;
+                }
+        }
+
+done:
+        free(line);
+        if (fp)
+                fclose(fp);
+        return value;
+}
+
+static uint64_t
+read_debugfs_u64_record(const char *file, const char *key)
+{
+        char *str_val = read_debugfs_record(file, key);
+        uint64_t val;
+
+        igt_require(str_val);
+
+        val = strtoull(str_val, NULL, 0);
+        free(str_val);
+
+        return val;
+}
+
+static bool
+lookup_hsw_render_basic_id(void)
+{
+        char buf[256];
+
+        snprintf(buf, sizeof(buf),
+                 "/sys/class/drm/card%d/metrics/403d8832-1a27-4aa6-a64e-f5389ce7b212/id",
+                 device);
+
+        return try_read_u64_file(buf, &hsw_render_basic_id);
+}
+
+static void
+gt_frequency_range_save(void)
+{
+        gt_min_freq_mhz_saved = sysfs_read("gt_min_freq_mhz");
+        gt_max_freq_mhz_saved = sysfs_read("gt_max_freq_mhz");
+
+        gt_min_freq_mhz = gt_min_freq_mhz_saved;
+        gt_max_freq_mhz = gt_max_freq_mhz_saved;
+}
+
+static void
+gt_frequency_pin(int gt_freq_mhz)
+{
+        igt_debug("requesting pinned GT freq = %dmhz\n", gt_freq_mhz);
+
+        if (gt_freq_mhz > gt_max_freq_mhz) {
+                sysfs_write("gt_max_freq_mhz", gt_freq_mhz);
+                sysfs_write("gt_min_freq_mhz", gt_freq_mhz);
+        } else {
+                sysfs_write("gt_min_freq_mhz", gt_freq_mhz);
+                sysfs_write("gt_max_freq_mhz", gt_freq_mhz);
+        }
+        gt_min_freq_mhz = gt_freq_mhz;
+        gt_max_freq_mhz = gt_freq_mhz;
+}
+
+static void
+gt_frequency_range_restore(void)
+{
+        igt_debug("restoring GT frequency range: min = %dmhz, max =%dmhz, current: min=%dmhz, max=%dmhz\n",
+                  (int)gt_min_freq_mhz_saved,
+                  (int)gt_max_freq_mhz_saved,
+                  (int)gt_min_freq_mhz,
+                  (int)gt_max_freq_mhz);
+
+        /* Assume current min/max are the same */
+        if (gt_min_freq_mhz_saved > gt_max_freq_mhz) {
+                sysfs_write("gt_max_freq_mhz", gt_max_freq_mhz_saved);
+                sysfs_write("gt_min_freq_mhz", gt_min_freq_mhz_saved);
+        } else {
+                sysfs_write("gt_min_freq_mhz", gt_min_freq_mhz_saved);
+                sysfs_write("gt_max_freq_mhz", gt_max_freq_mhz_saved);
+        }
+
+        gt_min_freq_mhz = gt_min_freq_mhz_saved;
+        gt_max_freq_mhz = gt_max_freq_mhz_saved;
+}
+
+static uint64_t
+timebase_scale(uint32_t u32_delta)
+{
+        return ((uint64_t)u32_delta * NSEC_PER_SEC) / timestamp_frequency;
+}
+
+/* CAP_SYS_ADMIN is required to open system wide metrics, unless the system
+ * control parameter dev.i915.perf_stream_paranoid == 0 */
+static void
+test_system_wide_paranoid(void)
+{
+        igt_fork(child, 1) {
+                uint64_t properties[] = {
+                        /* Include OA reports in samples */
+                        DRM_I915_PERF_PROP_SAMPLE_OA, true,
+
+                        /* OA unit configuration */
+                        DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
+                        DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
+                        DRM_I915_PERF_PROP_OA_EXPONENT, 13, /* 1 millisecond */
+                };
+                struct drm_i915_perf_open_param param = {
+                        .flags = I915_PERF_FLAG_FD_CLOEXEC |
+                                I915_PERF_FLAG_FD_NONBLOCK,
+                        .num_properties = sizeof(properties) / 16,
+                        .properties_ptr = (uint64_t)properties,
+                };
+
+                write_u64_file("/proc/sys/dev/i915/perf_stream_paranoid", 1);
+
+                igt_drop_root();
+
+                do_ioctl_err(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param, EACCES);
+        }
+
+        igt_waitchildren();
+
+        igt_fork(child, 1) {
+                uint64_t properties[] = {
+                        /* Include OA reports in samples */
+                        DRM_I915_PERF_PROP_SAMPLE_OA, true,
+
+                        /* OA unit configuration */
+                        DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
+                        DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
+                        DRM_I915_PERF_PROP_OA_EXPONENT, 13, /* 1 millisecond */
+                };
+                struct drm_i915_perf_open_param param = {
+                        .flags = I915_PERF_FLAG_FD_CLOEXEC |
+                                I915_PERF_FLAG_FD_NONBLOCK,
+                        .num_properties = sizeof(properties) / 16,
+                        .properties_ptr = (uint64_t)properties,
+                };
+                int stream_fd;
+
+                write_u64_file("/proc/sys/dev/i915/perf_stream_paranoid", 0);
+
+                igt_drop_root();
+
+                stream_fd = __perf_open(drm_fd, &param);
+                close(stream_fd);
+        }
+
+        igt_waitchildren();
+
+        /* leave in paranoid state */
+        write_u64_file("/proc/sys/dev/i915/perf_stream_paranoid", 1);
+}
+
+static void
+test_invalid_open_flags(void)
+{
+        uint64_t properties[] = {
+                /* Include OA reports in samples */
+                DRM_I915_PERF_PROP_SAMPLE_OA, true,
+
+                /* OA unit configuration */
+                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
+                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
+                DRM_I915_PERF_PROP_OA_EXPONENT, 13, /* 1 millisecond */
+        };
+        struct drm_i915_perf_open_param param = {
+                .flags = ~0, /* Undefined flag bits set! */
+                .num_properties = sizeof(properties) / 16,
+                .properties_ptr = (uint64_t)properties,
+        };
+
+        do_ioctl_err(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param, EINVAL);
+}
+
+static void
+test_invalid_oa_metric_set_id(void)
+{
+        uint64_t properties[] = {
+                /* Include OA reports in samples */
+                DRM_I915_PERF_PROP_SAMPLE_OA, true,
+
+                /* OA unit configuration */
+                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
+                DRM_I915_PERF_PROP_OA_EXPONENT, 13, /* 1 millisecond */
+                DRM_I915_PERF_PROP_OA_METRICS_SET, UINT64_MAX,
+        };
+        struct drm_i915_perf_open_param param = {
+                .flags = I915_PERF_FLAG_FD_CLOEXEC |
+                        I915_PERF_FLAG_FD_NONBLOCK,
+                .num_properties = sizeof(properties) / 16,
+                .properties_ptr = (uint64_t)properties,
+        };
+        int stream_fd;
+
+        do_ioctl_err(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param, EINVAL);
+
+        properties[ARRAY_SIZE(properties) - 1] = 0; /* ID 0 is also be reserved as invalid */
+        do_ioctl_err(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param, EINVAL);
+
+        /* Check that we aren't just seeing false positives... */
+        properties[ARRAY_SIZE(properties) - 1] = hsw_render_basic_id;
+        stream_fd = __perf_open(drm_fd, &param);
+        close(stream_fd);
+
+        /* There's no valid default OA metric set ID... */
+        param.num_properties--;
+        do_ioctl_err(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param, EINVAL);
+}
+
+static void
+test_invalid_oa_format_id(void)
+{
+        uint64_t properties[] = {
+                /* Include OA reports in samples */
+                DRM_I915_PERF_PROP_SAMPLE_OA, true,
+
+                /* OA unit configuration */
+                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
+                DRM_I915_PERF_PROP_OA_EXPONENT, 13, /* 1 millisecond */
+                DRM_I915_PERF_PROP_OA_FORMAT, UINT64_MAX,
+        };
+        struct drm_i915_perf_open_param param = {
+                .flags = I915_PERF_FLAG_FD_CLOEXEC |
+                        I915_PERF_FLAG_FD_NONBLOCK,
+                .num_properties = sizeof(properties) / 16,
+                .properties_ptr = (uint64_t)properties,
+        };
+        int stream_fd;
+
+        do_ioctl_err(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param, EINVAL);
+
+        properties[ARRAY_SIZE(properties) - 1] = 0; /* ID 0 is also be reserved as invalid */
+        do_ioctl_err(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param, EINVAL);
+
+        /* Check that we aren't just seeing false positives... */
+        properties[ARRAY_SIZE(properties) - 1] = I915_OA_FORMAT_A45_B8_C8;
+        stream_fd = __perf_open(drm_fd, &param);
+        close(stream_fd);
+
+        /* There's no valid default OA format... */
+        param.num_properties--;
+        do_ioctl_err(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param, EINVAL);
+}
+
+static void
+test_missing_sample_flags(void)
+{
+        uint64_t properties[] = {
+                /* No _PROP_SAMPLE_xyz flags */
+
+                /* OA unit configuration */
+                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
+                DRM_I915_PERF_PROP_OA_EXPONENT, 13, /* 1 millisecond */
+                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
+        };
+        struct drm_i915_perf_open_param param = {
+                .flags = I915_PERF_FLAG_FD_CLOEXEC,
+                .num_properties = sizeof(properties) / 16,
+                .properties_ptr = (uint64_t)properties,
+        };
+
+        do_ioctl_err(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param, EINVAL);
+}
+
+static void
+read_2_oa_reports(int stream_fd,
+                  uint64_t format_id,
+                  size_t format_size,
+                  int exponent,
+                  uint32_t *oa_report0,
+                  uint32_t *oa_report1,
+                  bool timer_only)
+{
+        size_t sample_size = (sizeof(struct drm_i915_perf_record_header) +
+                              format_size);
+        const struct drm_i915_perf_record_header *header;
+        uint32_t exponent_mask = (1 << (exponent + 1)) - 1;
+
+        /* Note: we allocate a large buffer so that each read() iteration
+         * should scrape *all* pending records.
+         *
+         * The largest buffer the OA unit supports is 16MB and the smallest
+         * OA report format is 64bytes allowing up to 262144 reports to
+         * be buffered.
+         *
+         * Being sure we are fetching all buffered reports allows us to
+         * potentially throw away / skip all reports whenever we see
+         * a _REPORT_LOST notification as a way of being sure are
+         * measurements aren't skewed by a lost report.
+         *
+         * Note: that is is useful for some tests but also not something
+         * applications would be expected to resort to. Lost reports are
+         * somewhat unpredictable but typically don't pose a problem - except
+         * to indicate that the OA unit may be over taxed if lots of reports
+         * are being lost.
+         */
+        int buf_size = 262144 * (64 + sizeof(struct drm_i915_perf_record_header));
+        uint8_t *buf = malloc(buf_size);
+        int n = 0;
+
+        for (int i = 0; i < 1000; i++) {
+                ssize_t len;
+
+                while ((len = read(stream_fd, buf, buf_size)) < 0 &&
+                       errno == EINTR)
+                        ;
+
+                igt_assert(len > 0);
+
+                for (size_t offset = 0; offset < len; offset += header->size) {
+                        const uint32_t *report;
+
+                        header = (void *)(buf + offset);
+
+                        igt_assert_eq(header->pad, 0); /* Reserved */
+
+                        /* Currently the only test that should ever expect to
+                         * see a _BUFFER_LOST error is the buffer_fill test,
+                         * otherwise something bad has probably happened...
+                         */
+                        igt_assert_neq(header->type, DRM_I915_PERF_RECORD_OA_BUFFER_LOST);
+
+                        /* At high sampling frequencies the OA HW might not be
+                         * able to cope with all write requests and will notify
+                         * us that a report was lost. We restart our read of
+                         * two sequential reports due to the timeline blip this
+                         * implies
+                         */
+                        if (header->type == DRM_I915_PERF_RECORD_OA_REPORT_LOST) {
+                                igt_debug("read restart: OA trigger collision / report lost\n");
+                                n = 0;
+
+                                /* XXX: break, because we don't know where
+                                 * within the series of already read reports
+                                 * there could be a blip from the lost report.
+                                 */
+                                break;
+                        }
+
+                        /* Currently the only other record type expected is a
+                         * _SAMPLE. Notably this test will need updating if
+                         * i915-perf is extended in the future with additional
+                         * record types.
+                         */
+                        igt_assert_eq(header->type, DRM_I915_PERF_RECORD_SAMPLE);
+
+                        igt_assert_eq(header->size, sample_size);
+
+                        report = (const void *)(header + 1);
+
+                        igt_debug("read report: reason = %x, timestamp = %x, exponent mask=%x\n",
+                                  report[0], report[1], exponent_mask);
+
+                        /* Don't expect zero for timestamps */
+                        igt_assert_neq(report[1], 0);
+
+                        if (timer_only) {
+                                /* For Haswell we don't have a documented
+                                 * report reason field (though empirically
+                                 * report[0] bit 10 does seem to correlate with
+                                 * a timer trigger reason) so we instead infer
+                                 * which reports are timer triggered by
+                                 * checking if the least significant bits are
+                                 * zero and the exponent bit is set.
+                                 */
+                                if ((report[1] & exponent_mask) != (1 << exponent)) {
+                                        igt_debug("skipping non timer report reason=%x\n",
+                                                  report[0]);
+
+                                        /* Also assert our hypothesis about the
+                                         * reason bit...
+                                         */
+                                        igt_assert_eq(report[0] & (1 << 10), 0);
+                                        continue;
+                                }
+                        }
+
+                        if (n++ == 0)
+                                memcpy(oa_report0, report, format_size);
+                        else {
+                                memcpy(oa_report1, report, format_size);
+                                free(buf);
+                                return;
+                        }
+                }
+        }
+
+        free(buf);
+
+        igt_assert(!"reached");
+}
+
+static void
+open_and_read_2_oa_reports(uint64_t format_id,
+                           size_t format_size,
+                           int exponent,
+                           uint32_t *oa_report0,
+                           uint32_t *oa_report1,
+                           bool timer_only)
+{
+        uint64_t properties[] = {
+                /* Include OA reports in samples */
+                DRM_I915_PERF_PROP_SAMPLE_OA, true,
+
+                /* OA unit configuration */
+                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
+                DRM_I915_PERF_PROP_OA_FORMAT, format_id,
+                DRM_I915_PERF_PROP_OA_EXPONENT, exponent,
+
+        };
+        struct drm_i915_perf_open_param param = {
+                .flags = I915_PERF_FLAG_FD_CLOEXEC,
+                .num_properties = sizeof(properties) / 16,
+                .properties_ptr = (uint64_t)properties,
+        };
+        int stream_fd = __perf_open(drm_fd, &param);
+
+        read_2_oa_reports(stream_fd, format_id, format_size, exponent,
+                          oa_report0, oa_report1, timer_only);
+
+        close(stream_fd);
+}
+
+static void
+print_reports(uint32_t *oa_report0, uint32_t *oa_report1, int fmt)
+{
+        uint32_t *a0, *b0, *c0;
+        uint32_t *a1, *b1, *c1;
+
+        /* Not ideal naming here with a0 or a1
+         * differentiating report0 or 1 not A counter 0 or 1....
+         */
+        a0 = (uint32_t *)(((uint8_t *)oa_report0) + hsw_oa_formats[fmt].a_off);
+        b0 = (uint32_t *)(((uint8_t *)oa_report0) + hsw_oa_formats[fmt].b_off);
+        c0 = (uint32_t *)(((uint8_t *)oa_report0) + hsw_oa_formats[fmt].c_off);
+
+        a1 = (uint32_t *)(((uint8_t *)oa_report1) + hsw_oa_formats[fmt].a_off);
+        b1 = (uint32_t *)(((uint8_t *)oa_report1) + hsw_oa_formats[fmt].b_off);
+        c1 = (uint32_t *)(((uint8_t *)oa_report1) + hsw_oa_formats[fmt].c_off);
+
+        igt_debug("TIMESTAMP: 1st = %"PRIu32", 2nd = %"PRIu32", delta = %"PRIu32"\n",
+                  oa_report0[1], oa_report1[1], oa_report1[1] - oa_report0[1]);
+
+        if (hsw_oa_formats[fmt].n_c) {
+                igt_debug("CLOCK: 1st = %"PRIu32", 2nd = %"PRIu32", delta = %"PRIu32"\n",
+                          c0[2], c1[2], c1[2] - c0[2]);
+        } else
+                igt_debug("CLOCK = N/A\n");
+
+        for (int j = hsw_oa_formats[fmt].first_a;
+             j < hsw_oa_formats[fmt].n_a;
+             j++)
+        {
+                uint32_t delta = a1[j] - a0[j];
+
+                if (hsw_undefined_a_counters[j])
+                        continue;
+
+                igt_debug("A%d: 1st = %"PRIu32", 2nd = %"PRIu32", delta = %"PRIu32"\n",
+                          j, a0[j], a1[j], delta);
+        }
+
+        for (int j = 0; j < hsw_oa_formats[fmt].n_b; j++) {
+                uint32_t delta = b1[j] - b0[j];
+                igt_debug("B%d: 1st = %"PRIu32", 2nd = %"PRIu32", delta = %"PRIu32"\n",
+                          j, b0[j], b1[j], delta);
+        }
+
+        for (int j = 0; j < hsw_oa_formats[fmt].n_c; j++) {
+                uint32_t delta = c1[j] - c0[j];
+                igt_debug("C%d: 1st = %"PRIu32", 2nd = %"PRIu32", delta = %"PRIu32"\n",
+                          j, c0[j], c1[j], delta);
+        }
+}
+
+static void
+test_oa_formats(void)
+{
+        int oa_exponent = 13;
+
+        for (int i = 0; i < ARRAY_SIZE(hsw_oa_formats); i++) {
+                uint32_t oa_report0[64];
+                uint32_t oa_report1[64];
+                uint32_t *a0, *b0, *c0;
+                uint32_t *a1, *b1, *c1;
+                uint32_t time_delta;
+                uint32_t clock_delta;
+                uint32_t max_delta;
+
+                igt_debug("Checking OA format %s\n", hsw_oa_formats[i].name);
+
+                open_and_read_2_oa_reports(hsw_oa_formats[i].id,
+                                           hsw_oa_formats[i].size,
+                                           oa_exponent,
+                                           oa_report0,
+                                           oa_report1,
+                                           false); /* timer reports only */
+
+                print_reports(oa_report0, oa_report1, i);
+
+                a0 = (uint32_t *)(((uint8_t *)oa_report0) + hsw_oa_formats[i].a_off);
+                b0 = (uint32_t *)(((uint8_t *)oa_report0) + hsw_oa_formats[i].b_off);
+                c0 = (uint32_t *)(((uint8_t *)oa_report0) + hsw_oa_formats[i].c_off);
+
+                a1 = (uint32_t *)(((uint8_t *)oa_report1) + hsw_oa_formats[i].a_off);
+                b1 = (uint32_t *)(((uint8_t *)oa_report1) + hsw_oa_formats[i].b_off);
+                c1 = (uint32_t *)(((uint8_t *)oa_report1) + hsw_oa_formats[i].c_off);
+
+                time_delta = timebase_scale(oa_report1[1] - oa_report0[1]);
+                igt_assert_neq(time_delta, 0);
+
+                /* C2 corresponds to a clock counter for this metric set but
+                 * it's not included in all of the formats. */
+                if (hsw_oa_formats[i].n_c) {
+                        uint64_t freq;
+
+                        /* The first report might have a clock count of zero
+                         * but we wouldn't expect that in the second report...
+                         */
+                        igt_assert_neq(c1[2], 0);
+
+                        clock_delta = c1[2] - c0[2];
+                        igt_assert_neq(clock_delta, 0);
+
+                        freq = ((uint64_t)clock_delta * 1000) / time_delta;
+                        igt_debug("freq = %"PRIu64"\n", freq);
+
+                        igt_assert(freq <= gt_max_freq_mhz);
+                } else {
+                        /* Assume running at max freq for sake of
+                         * below sanity check on counters... */
+                        clock_delta = (gt_max_freq_mhz *
+                                       (uint64_t)time_delta) / 1000;
+                }
+
+                igt_debug("clock delta = %"PRIu32"\n", clock_delta);
+
+                /* The maximum rate for any HSW counter =
+                 *   clock_delta * 40 EUs
+                 *
+                 * Sanity check that no counters exceed this delta.
+                 */
+                max_delta = clock_delta * 40;
+
+                for (int j = hsw_oa_formats[i].first_a;
+                     j < hsw_oa_formats[i].n_a;
+                     j++)
+                {
+                        uint32_t delta = a1[j] - a0[j];
+
+                        if (hsw_undefined_a_counters[j])
+                                continue;
+
+                        igt_debug("A%d: delta = %"PRIu32"\n", j, delta);
+                        igt_assert(delta <= max_delta);
+                }
+
+                for (int j = 0; j < hsw_oa_formats[i].n_b; j++) {
+                        uint32_t delta = b1[j] - b0[j];
+                        igt_debug("B%d: delta = %"PRIu32"\n", j, delta);
+                        igt_assert(delta <= max_delta);
+                }
+
+                for (int j = 0; j < hsw_oa_formats[i].n_c; j++) {
+                        uint32_t delta = c1[j] - c0[j];
+                        igt_debug("C%d: delta = %"PRIu32"\n", j, delta);
+                        igt_assert(delta <= max_delta);
+                }
+        }
+}
+
+static void
+test_oa_exponents(int gt_freq_mhz)
+{
+        /* XXX: Note that gt_min/max_freq_mhz don't seem to be a reliable
+         * mechanism for fixing the gpu frequency and since these unit tests
+         * are focused on the OA unit not the ability to pin the frequency we
+         * read back the current frequency for each iteration of this test to
+         * take this into account.
+         */
+        gt_frequency_pin(gt_freq_mhz);
+
+        igt_debug("Testing OA timer exponents with requested GT frequency = %dmhz\n",
+                  gt_freq_mhz);
+
+        /* It's asking a lot to sample with a 160 nanosecond period and the
+         * test can fail due to buffer overflows if it wasn't possible to
+         * keep up, so we don't start from an exponent of zero...
+         */
+        for (int i = 2; i < 20; i++) {
+                uint32_t expected_timestamp_delta;
+                uint32_t timestamp_delta;
+                uint32_t oa_report0[64];
+                uint32_t oa_report1[64];
+                uint32_t *c0, *c1;
+                uint32_t time_delta;
+                uint32_t clock_delta;
+                uint32_t freq;
+                int n_freq_matches = 0;
+
+                /* The exponent is effectively selecting a bit in the timestamp
+                 * to trigger reports on and so in practice we expect the raw
+                 * timestamp deltas for periodic reports to exactly match the
+                 * value of next bit.
+                 */
+                expected_timestamp_delta = 2 << i;
+
+                for (int j = 0; j < 10; j++) {
+                        gt_freq_mhz = sysfs_read("gt_act_freq_mhz");
+
+                        igt_debug("ITER %d: testing OA exponent %d with GT freq = %dmhz\n",
+                                  j, i, gt_freq_mhz);
+
+                        open_and_read_2_oa_reports(I915_OA_FORMAT_A45_B8_C8, 256,
+                                                   i, /* exponent */
+                                                   oa_report0,
+                                                   oa_report1,
+                                                   true); /* timer triggered
+                                                             reports only */
+
+                        timestamp_delta = oa_report1[1] - oa_report0[1];
+                        igt_assert_neq(timestamp_delta, 0);
+
+                        if (timestamp_delta != expected_timestamp_delta) {
+                                igt_debug("timestamp0 = %u/0x%x\n",
+                                          oa_report0[1], oa_report0[1]);
+                                igt_debug("timestamp1 = %u/0x%x\n",
+                                          oa_report1[1], oa_report1[1]);
+                        }
+
+                        igt_assert_eq(timestamp_delta, expected_timestamp_delta);
+
+                        c0 = (uint32_t *)(((uint8_t *)oa_report0) + 224 /* C offset */);
+                        c1 = (uint32_t *)(((uint8_t *)oa_report1) + 224 /* C offset */);
+                        clock_delta = c1[2] - c0[2];
+
+                        time_delta = timebase_scale(timestamp_delta);
+
+                        freq = ((uint64_t)clock_delta * 1000) / time_delta;
+                        igt_debug("ITER %d: time delta = %"PRIu32"(ns) clock delta = %"PRIu32" freq = %"PRIu32"(mhz)\n",
+                                  j, time_delta, clock_delta, freq);
+
+                        if (freq == gt_freq_mhz)
+                                n_freq_matches++;
+                }
+
+                igt_debug("number of iterations with expected clock frequency = %d\n",
+                          n_freq_matches);
+
+                /* Don't assert the calculated frequency for extremely short
+                 * durations... */
+                if (i > 3)
+                        igt_assert(n_freq_matches >= 7);
+        }
+
+        gt_frequency_range_restore();
+}
+
+/* The OA exponent selects a timestamp counter bit to trigger reports on.
+ *
+ * With a 64bit timestamp and least significant bit approx == 80ns then the MSB
+ * equates to > 40 thousand years and isn't exposed via the i915 perf interface.
+ *
+ * The max exponent exposed is expected to be 31, which is still a fairly
+ * ridiculous period (>5min) but is the maximum exponent where it's still
+ * possible to use periodic sampling as a means for tracking the overflow of
+ * 32bit OA report timestamps.
+ */
+static void
+test_invalid_oa_exponent(void)
+{
+        uint64_t properties[] = {
+                /* Include OA reports in samples */
+                DRM_I915_PERF_PROP_SAMPLE_OA, true,
+
+                /* OA unit configuration */
+                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
+                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
+                DRM_I915_PERF_PROP_OA_EXPONENT, 31, /* maximum exponent expected
+                                                       to be accepted */
+        };
+        struct drm_i915_perf_open_param param = {
+                .flags = I915_PERF_FLAG_FD_CLOEXEC,
+                .num_properties = sizeof(properties) / 16,
+                .properties_ptr = (uint64_t)properties,
+        };
+        int stream_fd = __perf_open(drm_fd, &param);
+
+        close(stream_fd);
+
+        for (int i = 32; i < 65; i++) {
+                properties[7] = i;
+                do_ioctl_err(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param, EINVAL);
+        }
+}
+
+/* Return the largest OA exponent that will still result in a sampling
+ * frequency higher than the given frequency.
+ */
+static int
+max_oa_exponent_for_higher_freq(uint64_t freq)
+{
+        /* NB: timebase_scale() takes a uint32_t and an exponent of 30
+         * would already represent a period of ~3 minutes so there's
+         * really no need to consider higher exponents.
+         */
+        for (int i = 0; i < 30; i++) {
+                uint64_t oa_period = timebase_scale(2 << i);
+                uint32_t oa_freq = NSEC_PER_SEC / oa_period;
+
+                if (oa_freq <= freq)
+                        return max(0, i - 1);
+        }
+
+        igt_assert(!"reached");
+        return -1;
+}
+
+/* The lowest periodic sampling exponent equates to a period of 160 nanoseconds
+ * or a frequency of 6.25MHz which is only possible to request as root by
+ * default. By default the maximum OA sampling rate is 100KHz
+ */
+static void
+test_low_oa_exponent_permissions(void)
+{
+        int max_freq = read_u64_file("/proc/sys/dev/i915/oa_max_sample_rate");
+        int bad_exponent = max_oa_exponent_for_higher_freq(max_freq);
+        int ok_exponent = bad_exponent + 1;
+        uint64_t properties[] = {
+                /* Include OA reports in samples */
+                DRM_I915_PERF_PROP_SAMPLE_OA, true,
+
+                /* OA unit configuration */
+                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
+                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
+                DRM_I915_PERF_PROP_OA_EXPONENT, bad_exponent,
+        };
+        struct drm_i915_perf_open_param param = {
+                .flags = I915_PERF_FLAG_FD_CLOEXEC,
+                .num_properties = sizeof(properties) / 16,
+                .properties_ptr = (uint64_t)properties,
+        };
+        uint64_t oa_period, oa_freq;
+
+        igt_assert_eq(max_freq, 100000);
+
+        /* Avoid EACCESS errors opening a stream without CAP_SYS_ADMIN */
+        write_u64_file("/proc/sys/dev/i915/perf_stream_paranoid", 0);
+
+        igt_fork(child, 1) {
+                igt_drop_root();
+
+                do_ioctl_err(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param, EACCES);
+        }
+
+        igt_waitchildren();
+
+        properties[7] = ok_exponent;
+
+        igt_fork(child, 1) {
+                int stream_fd;
+
+                igt_drop_root();
+
+                stream_fd = __perf_open(drm_fd, &param);
+                close(stream_fd);
+        }
+
+        igt_waitchildren();
+
+        oa_period = timebase_scale(2 << ok_exponent);
+        oa_freq = NSEC_PER_SEC / oa_period;
+        write_u64_file("/proc/sys/dev/i915/oa_max_sample_rate", oa_freq - 100);
+
+        igt_fork(child, 1) {
+                igt_drop_root();
+
+                do_ioctl_err(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param, EACCES);
+        }
+
+        igt_waitchildren();
+
+        /* restore the defaults */
+        write_u64_file("/proc/sys/dev/i915/oa_max_sample_rate", 100000);
+        write_u64_file("/proc/sys/dev/i915/perf_stream_paranoid", 1);
+}
+
+static void
+test_per_context_mode_unprivileged(void)
+{
+        uint64_t properties[] = {
+                /* Single context sampling */
+                DRM_I915_PERF_PROP_CTX_HANDLE, UINT64_MAX, /* updated below */
+
+                /* Include OA reports in samples */
+                DRM_I915_PERF_PROP_SAMPLE_OA, true,
+
+                /* OA unit configuration */
+                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
+                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
+                DRM_I915_PERF_PROP_OA_EXPONENT, 13, /* 1 millisecond */
+        };
+        struct drm_i915_perf_open_param param = {
+                .flags = I915_PERF_FLAG_FD_CLOEXEC,
+                .num_properties = sizeof(properties) / 16,
+                .properties_ptr = (uint64_t)properties,
+        };
+
+        /* should be default, but just to be sure... */
+        write_u64_file("/proc/sys/dev/i915/perf_stream_paranoid", 1);
+
+        igt_fork(child, 1) {
+                drm_intel_context *context;
+                drm_intel_bufmgr *bufmgr;
+                int stream_fd;
+
+                igt_drop_root();
+
+                bufmgr = drm_intel_bufmgr_gem_init(drm_fd, 4096);
+                context = drm_intel_gem_context_create(bufmgr);
+
+                igt_assert(context);
+
+                properties[1] = drm_intel_gem_context_get_context_id(context);
+
+                stream_fd = __perf_open(drm_fd, &param);
+                close(stream_fd);
+        }
+
+        igt_waitchildren();
+}
+
+static int64_t
+get_time(void)
+{
+        struct timespec ts;
+
+        clock_gettime(CLOCK_MONOTONIC, &ts);
+
+        return ts.tv_sec * 1000000000 + ts.tv_nsec;
+}
+
+/* Note: The interface doesn't currently provide strict guarantees or control
+ * over the upper bound for how long it might take for a POLLIN event after
+ * some OA report is written by the OA unit.
+ *
+ * The plan is to add a property later that gives some control over the maximum
+ * latency, but for now we expect it is tuned for a fairly low latency
+ * suitable for applications wanting to provide live feedback for captured
+ * metrics.
+ *
+ * At the time of writing this test the driver was using a fixed 200Hz hrtimer
+ * regardless of the OA sampling exponent.
+ *
+ * There is no lower bound since a stream configured for periodic sampling may
+ * still contain other automatically triggered reports.
+ *
+ * What we try and check for here is that blocking reads don't return EAGAIN
+ * and that we aren't spending any significant time burning the cpu in
+ * kernelspace.
+ */
+static void
+test_blocking(void)
+{
+        /* 40 milliseconds
+         *
+         * Having a period somewhat > sysconf(_SC_CLK_TCK) helps to stop
+         * scheduling (liable to kick in when we make blocking poll()s/reads)
+         * from interfering with the test.
+         */
+        int oa_exponent = 18;
+        uint64_t properties[] = {
+                /* Include OA reports in samples */
+                DRM_I915_PERF_PROP_SAMPLE_OA, true,
+
+                /* OA unit configuration */
+                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
+                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
+                DRM_I915_PERF_PROP_OA_EXPONENT, oa_exponent,
+        };
+        struct drm_i915_perf_open_param param = {
+                .flags = I915_PERF_FLAG_FD_CLOEXEC,
+                .num_properties = sizeof(properties) / 16,
+                .properties_ptr = (uint64_t)properties,
+        };
+        int stream_fd = __perf_open(drm_fd, &param);
+        uint8_t buf[1024 * 1024];
+        struct tms start_times;
+        struct tms end_times;
+        int64_t user_ns, kernel_ns;
+        int64_t tick_ns = 1000000000 / sysconf(_SC_CLK_TCK);
+        int64_t start;
+        int n = 0;
+
+        times(&start_times);
+
+        /* Loop for 600ms performing blocking reads while the HW is sampling at
+         * ~25Hz, with the expectation that we spend most of our time blocked
+         * in the kernel, and shouldn't be burning cpu cycles in the kernel in
+         * association with this process (verified by looking at stime before
+         * and after loop).
+         */
+        for (start = get_time(); (get_time() - start) < 600000000; /* nop */) {
+                int ret;
+
+                while ((ret = read(stream_fd, buf, sizeof(buf))) < 0 &&
+                       errno == EINTR)
+                        ;
+
+                igt_assert(ret > 0);
+
+                n++;
+        }
+
+        times(&end_times);
+
+        /* Using nanosecond units is fairly silly here, given the tick in-
+         * precision - ah well, it's consistent with the get_time() units.
+         */
+        user_ns = (end_times.tms_utime - start_times.tms_utime) * tick_ns;
+        kernel_ns = (end_times.tms_stime - start_times.tms_stime) * tick_ns;
+
+        igt_debug("%d blocking reads in 500 milliseconds, with 1KHz OA sampling\n", n);
+        igt_debug("time in userspace = %"PRIu64"ns (start utime = %d, end = %d, ns ticks per sec = %d)\n",
+                  user_ns, (int)start_times.tms_utime, (int)end_times.tms_utime, (int)tick_ns);
+        igt_debug("time in kernelspace = %"PRIu64"ns (start stime = %d, end = %d, ns ticks per sec = %d)\n",
+                  kernel_ns, (int)start_times.tms_stime, (int)end_times.tms_stime, (int)tick_ns);
+
+        /* With completely broken blocking (but also not returning an error) we
+         * could end up with an open loop, hopefully recognisable with > 15
+         * (600/40)iterations.
+         */
+        igt_assert(n <= 15);
+
+        /* It's a bit tricky to put a lower limit here, but we expect a
+         * relatively low latency for seeing reports, while we don't currently
+         * give any control over this in the api.
+         *
+         * Limited to a 5 millisecond latency and 45ms (worst case)
+         * per-iteration that could give 13.3 iterations. Rounding gives a tiny
+         * bit more latency slack (6ms)...
+         */
+        igt_assert(n > 13);
+
+        /* A bit tricky to put a number on this, but we don't expect the kernel
+         * to use any significant cpu while waiting and given the in precision
+         * of stime (multiple of CLK_TCK) we expect this to round to zero.
+         */
+        igt_assert_eq(kernel_ns, 0);
+
+        close(stream_fd);
+}
+
+static void
+test_polling(void)
+{
+        /* 40 milliseconds
+         *
+         * Having a period somewhat > sysconf(_SC_CLK_TCK) helps to stop
+         * scheduling (liable to kick in when we make blocking poll()s/reads)
+         * from interfering with the test.
+         */
+        int oa_exponent = 18;
+        uint64_t properties[] = {
+                /* Include OA reports in samples */
+                DRM_I915_PERF_PROP_SAMPLE_OA, true,
+
+                /* OA unit configuration */
+                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
+                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
+                DRM_I915_PERF_PROP_OA_EXPONENT, oa_exponent,
+        };
+        struct drm_i915_perf_open_param param = {
+                .flags = I915_PERF_FLAG_FD_CLOEXEC |
+                        I915_PERF_FLAG_FD_NONBLOCK,
+                .num_properties = sizeof(properties) / 16,
+                .properties_ptr = (uint64_t)properties,
+        };
+        int stream_fd = __perf_open(drm_fd, &param);
+        uint8_t buf[1024 * 1024];
+        struct tms start_times;
+        struct tms end_times;
+        int64_t user_ns, kernel_ns;
+        int64_t tick_ns = 1000000000 / sysconf(_SC_CLK_TCK);
+        int64_t start;
+        int n = 0;
+
+        times(&start_times);
+
+        /* Loop for 600ms performing blocking polls while the HW is sampling at
+         * ~25Hz, with the expectation that we spend most of our time blocked
+         * in the kernel, and shouldn't be burning cpu cycles in the kernel in
+         * association with this process (verified by looking at stime before
+         * and after loop).
+         */
+        for (start = get_time(); (get_time() - start) < 600000000; /* nop */) {
+                struct pollfd pollfd = { .fd = stream_fd, .events = POLLIN };
+                int ret;
+
+                while ((ret = poll(&pollfd, 1, -1)) < 0 &&
+                       errno == EINTR)
+                        ;
+                igt_assert_eq(ret, 1);
+                igt_assert(pollfd.revents & POLLIN);
+
+                while ((ret = read(stream_fd, buf, sizeof(buf))) < 0 &&
+                       errno == EINTR)
+                        ;
+
+                /* Don't expect to see EAGAIN if we've had a POLLIN event
+                 *
+                 * XXX: actually this is technically overly strict since we do
+                 * knowingly allow false positive POLLIN events. At least in
+                 * the future when supporting context filtering of metrics for
+                 * Gen8+ handled in the kernel then POLLIN events may be
+                 * delivered when we know there are pending reports to process
+                 * but before we've done any filtering to know for certain that
+                 * any reports are destined to be copied to userspace.
+                 *
+                 * Still, for now it's a reasonable sanity check.
+                 */
+                if (ret < 0)
+                        igt_debug("Unexpected error when reading after poll = %d\n", errno);
+                igt_assert_neq(ret, -1);
+
+                /* At this point, after consuming pending reports (and hoping
+                 * the scheduler hasn't stopped us for too long we now
+                 * expect EAGAIN on read.
+                 */
+                while ((ret = read(stream_fd, buf, sizeof(buf))) < 0 &&
+                       errno == EINTR)
+                        ;
+                igt_assert_eq(ret, -1);
+                igt_assert_eq(errno, EAGAIN);
+
+                n++;
+        }
+
+        times(&end_times);
+
+        /* Using nanosecond units is fairly silly here, given the tick in-
+         * precision - ah well, it's consistent with the get_time() units.
+         */
+        user_ns = (end_times.tms_utime - start_times.tms_utime) * tick_ns;
+        kernel_ns = (end_times.tms_stime - start_times.tms_stime) * tick_ns;
+
+        igt_debug("%d blocking poll()s in 600 milliseconds, with 25Hz OA sampling\n", n);
+        igt_debug("time in userspace = %"PRIu64"ns (start utime = %d, end = %d, ns ticks per sec = %d)\n",
+                  user_ns, (int)start_times.tms_utime, (int)end_times.tms_utime, (int)tick_ns);
+        igt_debug("time in kernelspace = %"PRIu64"ns (start stime = %d, end = %d, ns ticks per sec = %d)\n",
+                  kernel_ns, (int)start_times.tms_stime, (int)end_times.tms_stime, (int)tick_ns);
+
+        /* With completely broken blocking while polling (but still somehow
+         * reporting a POLLIN event) we could end up with an open loop,
+         * hopefully recognisable with > 15 (600/40)iterations.
+         */
+        igt_assert(n <= 15);
+
+        /* It's a bit tricky to put a lower limit here, but we expect a
+         * relatively low latency for seeing reports, while we don't currently
+         * give any control over this in the api.
+         *
+         * Limited to a 5 millisecond latency and 45ms (worst case)
+         * per-iteration that could give 13.3 iterations. Rounding gives a tiny
+         * bit more latency slack (6ms)...
+         */
+        igt_assert(n > 13);
+
+        /* A bit tricky to put a number on this, but we don't expect the kernel
+         * to use any significant cpu while waiting and given the in precision
+         * of stime (multiple of CLK_TCK) we expect this to round to zero.
+         */
+        igt_assert_eq(kernel_ns, 0);
+
+        close(stream_fd);
+}
+
+static void
+test_buffer_fill(void)
+{
+        int oa_exponent = 5; /* 5 micro seconds */
+        uint64_t properties[] = {
+                /* Include OA reports in samples */
+                DRM_I915_PERF_PROP_SAMPLE_OA, true,
+
+                /* OA unit configuration */
+                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
+                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
+                DRM_I915_PERF_PROP_OA_EXPONENT, oa_exponent,
+        };
+        struct drm_i915_perf_open_param param = {
+                .flags = I915_PERF_FLAG_FD_CLOEXEC,
+                .num_properties = sizeof(properties) / 16,
+                .properties_ptr = (uint64_t)properties,
+        };
+        int stream_fd = __perf_open(drm_fd, &param);
+        int buf_size = 65536 * (256 + sizeof(struct drm_i915_perf_record_header));
+        uint8_t *buf = malloc(buf_size);
+
+
+        for (int i = 0; i < 5; i++) {
+                struct drm_i915_perf_record_header *header;
+                bool overflow_seen;
+                int offset = 0;
+                int len;
+
+                /* It should take ~330 milliseconds to fill a 16MB OA buffer with a
+                 * 5 microsecond sampling period and 256 byte reports. */
+                nanosleep(&(struct timespec){ .tv_sec = 0, .tv_nsec = 500000000 }, NULL);
+
+                while ((len = read(stream_fd, buf, buf_size)) == -1 && errno == EINTR)
+                        ;
+
+                igt_assert_neq(len, -1);
+
+                overflow_seen = false;
+                for (offset = 0; offset < len; offset += header->size) {
+                        header = (void *)(buf + offset);
+
+                        if (header->type == DRM_I915_PERF_RECORD_OA_BUFFER_LOST)
+                                overflow_seen = true;
+                }
+
+                igt_assert_eq(overflow_seen, true);
+
+                nanosleep(&(struct timespec){ .tv_sec = 0, .tv_nsec = 1000000 }, NULL);
+
+                while ((len = read(stream_fd, buf, buf_size)) == -1 && errno == EINTR)
+                        ;
+
+                igt_assert_neq(len, -1);
+
+                /* expect ~ 200 records in 1 millisecond */
+                igt_assert(len > 256 * 150);
+
+                overflow_seen = false;
+                for (offset = 0; offset < len; offset += header->size) {
+                        header = (void *)(buf + offset);
+
+                        if (header->type == DRM_I915_PERF_RECORD_OA_BUFFER_LOST)
+                                overflow_seen = true;
+                }
+
+                igt_assert_eq(overflow_seen, false);
+        }
+
+        free(buf);
+
+        close(stream_fd);
+}
+
+static void
+test_enable_disable(void)
+{
+        int oa_exponent = 5; /* 5 micro seconds */
+        uint64_t properties[] = {
+                /* Include OA reports in samples */
+                DRM_I915_PERF_PROP_SAMPLE_OA, true,
+
+                /* OA unit configuration */
+                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
+                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
+                DRM_I915_PERF_PROP_OA_EXPONENT, oa_exponent,
+        };
+        struct drm_i915_perf_open_param param = {
+                .flags = I915_PERF_FLAG_FD_CLOEXEC |
+                         I915_PERF_FLAG_DISABLED, /* Verify we start disabled */
+                .num_properties = sizeof(properties) / 16,
+                .properties_ptr = (uint64_t)properties,
+        };
+        int stream_fd = __perf_open(drm_fd, &param);
+        int buf_size = 65536 * (256 + sizeof(struct drm_i915_perf_record_header));
+        uint8_t *buf = malloc(buf_size);
+
+
+        for (int i = 0; i < 5; i++) {
+                int len;
+
+                /* If the stream were enabled then it would take ~330
+                 * milliseconds to fill a 16MB OA buffer with a 5 microsecond
+                 * sampling period and 256 byte reports.
+                 *
+                 * Giving enough time for an overflow might help catch whether
+                 * the OA unit has been enabled even if the driver might at
+                 * least avoid copying reports while disabled.
+                 */
+                nanosleep(&(struct timespec){ .tv_sec = 0, .tv_nsec = 500000000 }, NULL);
+
+                while ((len = read(stream_fd, buf, buf_size)) == -1 && errno == EINTR)
+                        ;
+
+                igt_assert_eq(len, -1);
+                igt_assert_eq(errno, EIO);
+
+                do_ioctl(stream_fd, I915_PERF_IOCTL_ENABLE, 0);
+
+                nanosleep(&(struct timespec){ .tv_sec = 0, .tv_nsec = 1000000 }, NULL);
+
+                while ((len = read(stream_fd, buf, buf_size)) == -1 && errno == EINTR)
+                        ;
+
+                igt_assert_neq(len, -1);
+
+                /* expect ~ 200 records in 1 millisecond */
+                igt_assert(len > 256 * 150 && len < 256 * 2000);
+
+                do_ioctl(stream_fd, I915_PERF_IOCTL_DISABLE, 0);
+
+                /* It's considered an error to read a stream while it's disabled
+                 * since it would block indefinitely...
+                 */
+                len = read(stream_fd, buf, buf_size);
+
+                igt_assert_eq(len, -1);
+                igt_assert_eq(errno, EIO);
+        }
+
+        free(buf);
+
+        close(stream_fd);
+}
+
+static void
+test_short_reads(void)
+{
+        int oa_exponent = 5; /* 5 micro seconds */
+        uint64_t properties[] = {
+                /* Include OA reports in samples */
+                DRM_I915_PERF_PROP_SAMPLE_OA, true,
+
+                /* OA unit configuration */
+                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
+                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
+                DRM_I915_PERF_PROP_OA_EXPONENT, oa_exponent,
+        };
+        struct drm_i915_perf_open_param param = {
+                .flags = I915_PERF_FLAG_FD_CLOEXEC,
+                .num_properties = sizeof(properties) / 16,
+                .properties_ptr = (uint64_t)properties,
+        };
+        size_t record_size = 256 + sizeof(struct drm_i915_perf_record_header);
+        size_t page_size = sysconf(_SC_PAGE_SIZE);
+        int zero_fd = open("/dev/zero", O_RDWR|O_CLOEXEC);
+        uint8_t *pages = mmap(NULL, page_size * 2,
+                              PROT_READ|PROT_WRITE, MAP_PRIVATE, zero_fd, 0);
+        struct drm_i915_perf_record_header *header;
+        int stream_fd;
+        int ret;
+
+        igt_assert(pages);
+
+        ret = mprotect(pages + page_size, page_size, PROT_NONE);
+        igt_assert_eq(ret, 0);
+
+        stream_fd = __perf_open(drm_fd, &param);
+
+        nanosleep(&(struct timespec){ .tv_sec = 0, .tv_nsec = 5000000 }, NULL);
+
+        /* At this point there should be lots of pending reports to read */
+
+        /* A read that can return at least one record should result in a short
+         * read not an EFAULT if the buffer is smaller than the requested read
+         * size...
+         *
+         * Expect to see a sample record here, but at least skip over any
+         * _RECORD_LOST notifications.
+         */
+        do {
+                header = (void *)(pages + page_size - record_size);
+                ret = read(stream_fd,
+                           header,
+                           page_size);
+                igt_assert(ret > 0);
+        } while (header->type == DRM_I915_PERF_RECORD_OA_REPORT_LOST);
+
+        igt_assert_eq(ret, record_size);
+
+        /* A read that can't return a single record because it would result
+         * in a fault on buffer overrun should result in an EFAULT error...
+         */
+        ret = read(stream_fd, pages + page_size - 16, page_size);
+        igt_assert_eq(ret, -1);
+        igt_assert_eq(errno, EFAULT);
+
+        /* A read that can't return a single record because the buffer is too
+         * small should result in an ENOSPC error..
+         *
+         * Again, skip over _RECORD_LOST records (smaller than record_size/2)
+         */
+        do {
+                header = (void *)(pages + page_size - record_size / 2);
+                ret = read(stream_fd,
+                           header,
+                           record_size / 2);
+        } while (ret > 0 && header->type == DRM_I915_PERF_RECORD_OA_REPORT_LOST);
+
+        igt_assert_eq(ret, -1);
+        igt_assert_eq(errno, ENOSPC);
+
+        close(stream_fd);
+}
+
+static void
+test_non_sampling_read_error(void)
+{
+        uint64_t properties[] = {
+                /* XXX: even without periodic sampling we have to
+                 * specify at least one sample layout property...
+                 */
+                DRM_I915_PERF_PROP_SAMPLE_OA, true,
+
+                /* OA unit configuration */
+                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
+                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
+
+                /* XXX: no sampling exponent */
+        };
+        struct drm_i915_perf_open_param param = {
+                .flags = I915_PERF_FLAG_FD_CLOEXEC,
+                .num_properties = sizeof(properties) / 16,
+                .properties_ptr = (uint64_t)properties,
+        };
+        int stream_fd = __perf_open(drm_fd, &param);
+        uint8_t buf[1024];
+
+        int ret = read(stream_fd, buf, sizeof(buf));
+        igt_assert_eq(ret, -1);
+        igt_assert_eq(errno, EIO);
+
+        close(stream_fd);
+}
+
+/* Check that attempts to read from a stream while it is disable will return
+ * EIO instead of blocking indefinitely.
+ */
+static void
+test_disabled_read_error(void)
+{
+        int oa_exponent = 5; /* 5 micro seconds */
+        uint64_t properties[] = {
+                /* XXX: even without periodic sampling we have to
+                 * specify at least one sample layout property...
+                 */
+                DRM_I915_PERF_PROP_SAMPLE_OA, true,
+
+                /* OA unit configuration */
+                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
+                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
+                DRM_I915_PERF_PROP_OA_EXPONENT, oa_exponent,
+        };
+        struct drm_i915_perf_open_param param = {
+                .flags = I915_PERF_FLAG_FD_CLOEXEC |
+                         I915_PERF_FLAG_DISABLED, /* XXX: open disabled */
+                .num_properties = sizeof(properties) / 16,
+                .properties_ptr = (uint64_t)properties,
+        };
+        int stream_fd = __perf_open(drm_fd, &param);
+        uint32_t oa_report0[64];
+        uint32_t oa_report1[64];
+        uint32_t buf[128] = { 0 };
+        int ret;
+
+
+        ret = read(stream_fd, buf, sizeof(buf));
+        igt_assert_eq(ret, -1);
+        igt_assert_eq(errno, EIO);
+
+        close(stream_fd);
+
+
+        param.flags &= ~I915_PERF_FLAG_DISABLED;
+        stream_fd = __perf_open(drm_fd, &param);
+
+        read_2_oa_reports(stream_fd,
+                          I915_OA_FORMAT_A45_B8_C8, 256,
+                          oa_exponent,
+                          oa_report0,
+                          oa_report1,
+                          false); /* not just timer reports */
+
+        do_ioctl(stream_fd, I915_PERF_IOCTL_DISABLE, 0);
+
+        ret = read(stream_fd, buf, sizeof(buf));
+        igt_assert_eq(ret, -1);
+        igt_assert_eq(errno, EIO);
+
+        do_ioctl(stream_fd, I915_PERF_IOCTL_ENABLE, 0);
+
+        read_2_oa_reports(stream_fd,
+                          I915_OA_FORMAT_A45_B8_C8, 256,
+                          oa_exponent,
+                          oa_report0,
+                          oa_report1,
+                          false); /* not just timer reports */
+
+        close(stream_fd);
+}
+
+static void
+test_mi_rpc(void)
+{
+        uint64_t properties[] = {
+                /* Note: we have to specify at least one sample property even
+                 * though we aren't interested in samples in this case.
+                 */
+                DRM_I915_PERF_PROP_SAMPLE_OA, true,
+
+                /* OA unit configuration */
+                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
+                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
+
+                /* Note: no OA exponent specified in this case */
+        };
+        struct drm_i915_perf_open_param param = {
+                .flags = I915_PERF_FLAG_FD_CLOEXEC,
+                .num_properties = sizeof(properties) / 16,
+                .properties_ptr = (uint64_t)properties,
+        };
+        int stream_fd = __perf_open(drm_fd, &param);
+        drm_intel_bufmgr *bufmgr = drm_intel_bufmgr_gem_init(drm_fd, 4096);
+        drm_intel_context *context;
+        struct intel_batchbuffer *batch;
+        drm_intel_bo *bo;
+        uint32_t *report32;
+        int ret;
+
+        drm_intel_bufmgr_gem_enable_reuse(bufmgr);
+
+        context = drm_intel_gem_context_create(bufmgr);
+        igt_assert(context);
+
+        batch = intel_batchbuffer_alloc(bufmgr, devid);
+
+        bo = drm_intel_bo_alloc(bufmgr, "mi_rpc dest bo", 4096, 64);
+
+        ret = drm_intel_bo_map(bo, true);
+        igt_assert_eq(ret, 0);
+
+        memset(bo->virtual, 0x80, 4096);
+        drm_intel_bo_unmap(bo);
+
+        BEGIN_BATCH(3, 1);
+        OUT_BATCH(GEN6_MI_REPORT_PERF_COUNT);
+        OUT_RELOC(bo, I915_GEM_DOMAIN_INSTRUCTION, I915_GEM_DOMAIN_INSTRUCTION,
+                  0); /* offset in bytes */
+        OUT_BATCH(0xdeadbeef); /* report ID */
+        ADVANCE_BATCH();
+
+        intel_batchbuffer_flush_with_context(batch, context);
+
+        ret = drm_intel_bo_map(bo, false /* write enable */);
+        igt_assert_eq(ret, 0);
+
+        report32 = bo->virtual;
+        igt_assert_eq(report32[0], 0xdeadbeef); /* report ID */
+        igt_assert_neq(report32[1], 0); /* timestamp */
+
+        igt_assert_neq(report32[63], 0x80808080); /* end of report */
+        igt_assert_eq(report32[64], 0x80808080); /* after 256 byte report */
+
+        intel_batchbuffer_free(batch);
+        drm_intel_gem_context_destroy(context);
+        drm_intel_bufmgr_destroy(bufmgr);
+        close(stream_fd);
+}
+
+static void
+scratch_buf_init(drm_intel_bufmgr *bufmgr,
+                 struct igt_buf *buf,
+                 int width, int height,
+                 uint32_t color)
+{
+        size_t stride = width * 4;
+        size_t size = stride * height;
+	drm_intel_bo *bo = drm_intel_bo_alloc(bufmgr, "", size, 4096);
+        int ret;
+
+        ret = drm_intel_bo_map(bo, true /* writable */);
+        igt_assert_eq(ret, 0);
+
+        for (int i = 0; i < width * height; i++)
+                ((uint32_t *)bo->virtual)[i] = color;
+
+        drm_intel_bo_unmap(bo);
+
+	buf->bo = bo;
+	buf->stride = stride;
+	buf->tiling = I915_TILING_NONE;
+	buf->size = size;
+}
+
+static void
+emit_stall_timestamp_and_rpc(struct intel_batchbuffer *batch,
+                             drm_intel_bo *dst,
+                             int timestamp_offset,
+                             int report_dst_offset,
+                             uint32_t report_id)
+{
+        uint32_t pipe_ctl_flags = (PIPE_CONTROL_CS_STALL |
+                                   PIPE_CONTROL_RENDER_TARGET_FLUSH |
+                                   PIPE_CONTROL_WRITE_TIMESTAMP);
+
+        BEGIN_BATCH(5, 1);
+        OUT_BATCH(GFX_OP_PIPE_CONTROL | (5 - 2));
+        OUT_BATCH(pipe_ctl_flags);
+        OUT_RELOC(dst, I915_GEM_DOMAIN_INSTRUCTION, I915_GEM_DOMAIN_INSTRUCTION,
+                  timestamp_offset);
+        OUT_BATCH(0); /* imm lower */
+        OUT_BATCH(0); /* imm upper */
+        ADVANCE_BATCH();
+
+        BEGIN_BATCH(3, 1);
+        OUT_BATCH(GEN6_MI_REPORT_PERF_COUNT);
+        OUT_RELOC(dst, I915_GEM_DOMAIN_INSTRUCTION, I915_GEM_DOMAIN_INSTRUCTION,
+                  report_dst_offset);
+        OUT_BATCH(report_id);
+        ADVANCE_BATCH();
+}
+
+/* Tests the INTEL_performance_query use case where an unprivileged process
+ * should be able to configure the OA unit for per-context metrics (for a
+ * context associated with that process' drm file descriptor) and the counters
+ * should only relate to that specific context.
+ */
+static void
+test_per_ctx_mi_rpc(void)
+{
+        uint64_t properties[] = {
+                DRM_I915_PERF_PROP_CTX_HANDLE, UINT64_MAX, /* updated below */
+
+                /* Note: we have to specify at least one sample property even
+                 * though we aren't interested in samples in this case
+                 */
+                DRM_I915_PERF_PROP_SAMPLE_OA, true,
+
+                /* OA unit configuration */
+                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
+                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
+
+                /* Note: no OA exponent specified in this case */
+        };
+        struct drm_i915_perf_open_param param = {
+                .flags = I915_PERF_FLAG_FD_CLOEXEC,
+                .num_properties = sizeof(properties) / 16,
+                .properties_ptr = (uint64_t)properties,
+        };
+
+        /* should be default, but just to be sure... */
+        write_u64_file("/proc/sys/dev/i915/perf_stream_paranoid", 1);
+
+        igt_fork(child, 1) {
+                drm_intel_bufmgr *bufmgr;
+                drm_intel_context *context0, *context1;
+                int stream_fd;
+                struct intel_batchbuffer *batch;
+                struct igt_buf src, dst;
+                drm_intel_bo *bo;
+                uint32_t *report0_32, *report1_32;
+                uint64_t timestamp0_64, timestamp1_64;
+                uint32_t delta_ts64, delta_oa32;
+                uint64_t delta_ts64_ns, delta_oa32_ns;
+                uint32_t delta_delta;
+                int n_samples_written;
+                int width = 800;
+                int height = 600;
+                int ret;
+
+                igt_drop_root();
+
+                bufmgr = drm_intel_bufmgr_gem_init(drm_fd, 4096);
+                drm_intel_bufmgr_gem_enable_reuse(bufmgr);
+
+                scratch_buf_init(bufmgr, &src, width, height, 0xff0000ff);
+                scratch_buf_init(bufmgr, &dst, width, height, 0x00ff00ff);
+
+                batch = intel_batchbuffer_alloc(bufmgr, devid);
+
+                context0 = drm_intel_gem_context_create(bufmgr);
+                igt_assert(context0);
+
+                context1 = drm_intel_gem_context_create(bufmgr);
+                igt_assert(context1);
+
+                igt_debug("submitting warm up render_copy\n");
+
+                /* Submit some early, unmeasured, work to the context we want
+                 * to measure to try and catch issues with i915-perf
+                 * initializing the HW context ID for filtering.
+                 *
+                 * We do this because i915-perf single context filtering had
+                 * previously only relied on a hook into context pinning to
+                 * initialize the HW context ID, instead of also trying to
+                 * determine the HW ID while opening the stream, in case it
+                 * has already been pinned.
+                 *
+                 * This wasn't noticed by the previous unit test because we
+                 * were opening the stream while the context hadn't been
+                 * touched or pinned yet and so it worked out correctly to wait
+                 * for the pinning hook.
+                 *
+                 * Now a buggy version of i915-perf will fail to measure
+                 * anything for context0 once this initial render_copy() ends
+                 * up pinning the context since there won't ever be a pinning
+                 * hook callback.
+                 */
+                render_copy(batch,
+                            context0,
+                            &src, 0, 0, width, height,
+                            &dst, 0, 0);
+
+                properties[1] = drm_intel_gem_context_get_context_id(context0);
+
+                igt_debug("opening i915-perf stream\n");
+                stream_fd = __perf_open(drm_fd, &param);
+
+                bo = drm_intel_bo_alloc(bufmgr, "mi_rpc dest bo", 4096, 64);
+
+                ret = drm_intel_bo_map(bo, true /* write enable */);
+                igt_assert_eq(ret, 0);
+
+                memset(bo->virtual, 0x80, 4096);
+                drm_intel_bo_unmap(bo);
+
+                emit_stall_timestamp_and_rpc(batch,
+                                             bo,
+                                             512 /* timestamp offset */,
+                                             0, /* report dst offset */
+                                             0xdeadbeef); /* report id */
+
+                /* Explicitly flush here (even though the render_copy() call
+                 * will itself flush before/after the copy) to clarify that
+                 * that the PIPE_CONTROL + MI_RPC commands will be in a
+                 * separate batch from the copy.
+                 */
+                intel_batchbuffer_flush_with_context(batch, context0);
+
+                render_copy(batch,
+                            context0,
+                            &src, 0, 0, width, height,
+                            &dst, 0, 0);
+
+                /* Another redundant flush to clarify batch bo is free to reuse */
+                intel_batchbuffer_flush_with_context(batch, context0);
+
+                /* submit two copies on the other context to avoid a false
+                 * positive in case the driver somehow ended up filtering for
+                 * context1
+                 */
+                render_copy(batch,
+                            context1,
+                            &src, 0, 0, width, height,
+                            &dst, 0, 0);
+
+                render_copy(batch,
+                            context1,
+                            &src, 0, 0, width, height,
+                            &dst, 0, 0);
+
+                /* And another */
+                intel_batchbuffer_flush_with_context(batch, context1);
+
+                emit_stall_timestamp_and_rpc(batch,
+                                             bo,
+                                             520 /* timestamp offset */,
+                                             256, /* report dst offset */
+                                             0xbeefbeef); /* report id */
+
+                intel_batchbuffer_flush_with_context(batch, context0);
+
+                ret = drm_intel_bo_map(bo, false /* write enable */);
+                igt_assert_eq(ret, 0);
+
+                report0_32 = bo->virtual;
+                igt_assert_eq(report0_32[0], 0xdeadbeef); /* report ID */
+                igt_assert_neq(report0_32[1], 0); /* timestamp */
+
+                report1_32 = report0_32 + 64;
+                igt_assert_eq(report1_32[0], 0xbeefbeef); /* report ID */
+                igt_assert_neq(report1_32[1], 0); /* timestamp */
+
+                print_reports(report0_32, report1_32,
+                              lookup_format(I915_OA_FORMAT_A45_B8_C8));
+
+                /* A40 == N samples written to all render targets */
+                n_samples_written = report1_32[43] - report0_32[43];
+                igt_debug("n samples written = %d\n", n_samples_written);
+                igt_assert_eq(n_samples_written, width * height);
+
+                igt_debug("timestamp32 0 = %u\n", report0_32[1]);
+                igt_debug("timestamp32 1 = %u\n", report1_32[1]);
+
+                timestamp0_64 = *(uint64_t *)(((uint8_t *)bo->virtual) + 512);
+                timestamp1_64 = *(uint64_t *)(((uint8_t *)bo->virtual) + 520);
+
+                igt_debug("timestamp64 0 = %"PRIu64"\n", timestamp0_64);
+                igt_debug("timestamp64 1 = %"PRIu64"\n", timestamp1_64);
+
+                delta_ts64 = timestamp1_64 - timestamp0_64;
+                delta_oa32 = report1_32[1] - report0_32[1];
+
+                /* sanity check that we can pass the delta to timebase_scale */
+                igt_assert(delta_ts64 < UINT32_MAX);
+                delta_oa32_ns = timebase_scale(delta_oa32);
+                delta_ts64_ns = timebase_scale(delta_ts64);
+
+                igt_debug("ts32 delta = %u, = %uns\n",
+                          delta_oa32, (unsigned)delta_oa32_ns);
+                igt_debug("ts64 delta = %u, = %uns\n",
+                          delta_ts64, (unsigned)delta_ts64_ns);
+
+                /* The delta as calculated via the PIPE_CONTROL timestamp or
+                 * the OA report timestamps should be almost identical but
+                 * allow a 320 nanoseconds margin.
+                 */
+                delta_delta = delta_ts64_ns > delta_oa32_ns ?
+                        (delta_ts64_ns - delta_oa32_ns) :
+                        (delta_oa32_ns - delta_ts64_ns);
+                igt_assert(delta_delta <= 320);
+
+                intel_batchbuffer_free(batch);
+                drm_intel_gem_context_destroy(context0);
+                drm_intel_gem_context_destroy(context1);
+                drm_intel_bufmgr_destroy(bufmgr);
+                close(stream_fd);
+        }
+
+        igt_waitchildren();
+}
+
+static void
+test_rc6_disable(void)
+{
+        int oa_exponent = 13; /* 1 millisecond */
+        uint64_t properties[] = {
+                /* Include OA reports in samples */
+                DRM_I915_PERF_PROP_SAMPLE_OA, true,
+
+                /* OA unit configuration */
+                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
+                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
+                DRM_I915_PERF_PROP_OA_EXPONENT, oa_exponent,
+        };
+        struct drm_i915_perf_open_param param = {
+                .flags = I915_PERF_FLAG_FD_CLOEXEC,
+                .num_properties = sizeof(properties) / 16,
+                .properties_ptr = (uint64_t)properties,
+        };
+        int stream_fd = __perf_open(drm_fd, &param);
+        uint64_t n_events_start = read_debugfs_u64_record("i915_drpc_info",
+                                                          "RC6 residency since boot");
+        uint64_t n_events_end;
+
+        nanosleep(&(struct timespec){ .tv_sec = 0, .tv_nsec = 500000000 }, NULL);
+
+        n_events_end = read_debugfs_u64_record("i915_drpc_info",
+                                               "RC6 residency since boot");
+
+        igt_assert_eq(n_events_end - n_events_start, 0);
+
+        close(stream_fd);
+
+        n_events_start = read_debugfs_u64_record("i915_drpc_info",
+                                                 "RC6 residency since boot");
+
+        nanosleep(&(struct timespec){ .tv_sec = 0, .tv_nsec = 500000000 }, NULL);
+
+        n_events_end = read_debugfs_u64_record("i915_drpc_info",
+                                               "RC6 residency since boot");
+
+        igt_assert_neq(n_events_end - n_events_start, 0);
+}
+
+static unsigned
+read_i915_module_ref(void)
+{
+        FILE *fp = fopen("/proc/modules", "r");
+        char *line = NULL;
+        size_t line_buf_size = 0;
+        int len = 0;
+        unsigned ref_count;
+
+        igt_assert(fp);
+
+        while ((len = getline(&line, &line_buf_size, fp)) > 0) {
+                if (strncmp(line, "i915 ", 5) == 0) {
+                        unsigned long mem;
+                        int ret = sscanf(line + 5, "%lu %u", &mem, &ref_count);
+                        igt_assert(ret == 2);
+                        goto done;
+                }
+        }
+
+        igt_assert(!"reached");
+
+done:
+        free(line);
+        fclose(fp);
+        return ref_count;
+}
+
+/* check that an open i915 perf stream holds a reference on the drm i915 module
+ * including in the corner case where the original drm fd has been closed.
+ */
+static void
+test_i915_ref_count(void)
+{
+        int oa_exponent = 13; /* 1 millisecond */
+        uint64_t properties[] = {
+                /* Include OA reports in samples */
+                DRM_I915_PERF_PROP_SAMPLE_OA, true,
+
+                /* OA unit configuration */
+                DRM_I915_PERF_PROP_OA_METRICS_SET, hsw_render_basic_id,
+                DRM_I915_PERF_PROP_OA_FORMAT, I915_OA_FORMAT_A45_B8_C8,
+                DRM_I915_PERF_PROP_OA_EXPONENT, oa_exponent,
+        };
+        struct drm_i915_perf_open_param param = {
+                .flags = I915_PERF_FLAG_FD_CLOEXEC,
+                .num_properties = sizeof(properties) / 16,
+                .properties_ptr = (uint64_t)properties,
+        };
+        unsigned baseline, ref_count0, ref_count1;
+        int stream_fd;
+        uint32_t oa_report0[64];
+        uint32_t oa_report1[64];
+
+        close(drm_fd);
+        baseline = read_i915_module_ref();
+        igt_debug("baseline ref count (drm fd closed) = %u\n", baseline);
+
+        drm_fd = drm_open_driver_render(DRIVER_INTEL);
+        ref_count0 = read_i915_module_ref();
+        igt_debug("initial ref count with drm_fd open = %u\n", ref_count0);
+        igt_assert(ref_count0 > baseline);
+
+        stream_fd = __perf_open(drm_fd, &param);
+        ref_count1 = read_i915_module_ref();
+        igt_debug("ref count after opening i915 perf stream = %u\n", ref_count1);
+        igt_assert(ref_count1 > ref_count0);
+
+        close(drm_fd);
+        ref_count0 = read_i915_module_ref();
+        igt_debug("ref count after closing drm fd = %u\n", ref_count0);
+
+        igt_assert(ref_count0 > baseline);
+
+        read_2_oa_reports(stream_fd,
+                          I915_OA_FORMAT_A45_B8_C8, 256,
+                          oa_exponent,
+                          oa_report0,
+                          oa_report1,
+                          false); /* not just timer reports */
+
+        close(stream_fd);
+        ref_count0 = read_i915_module_ref();
+        igt_debug("ref count after closing i915 perf stream fd = %u\n", ref_count0);
+        igt_assert_eq(ref_count0, baseline);
+
+        drm_fd = drm_open_driver_render(DRIVER_INTEL);
+}
+
+igt_main
+{
+        igt_skip_on_simulation();
+
+        igt_fixture {
+                struct stat sb;
+                int ret;
+
+                drm_fd = drm_open_driver_render(DRIVER_INTEL);
+                devid = intel_get_drm_devid(drm_fd);
+                device = drm_get_card();
+
+                igt_require(IS_HASWELL(devid));
+                igt_require(lookup_hsw_render_basic_id());
+
+                ret = stat("/proc/sys/dev/i915/perf_stream_paranoid", &sb);
+                igt_require(ret == 0);
+                ret = stat("/proc/sys/dev/i915/oa_max_sample_rate", &sb);
+                igt_require(ret == 0);
+
+                gt_frequency_range_save();
+
+                write_u64_file("/proc/sys/dev/i915/perf_stream_paranoid", 1);
+
+                render_copy = igt_get_render_copyfunc(devid);
+                igt_require_f(render_copy, "no render-copy function\n");
+        }
+
+        igt_subtest("non-system-wide-paranoid")
+                test_system_wide_paranoid();
+
+        igt_subtest("invalid-open-flags")
+                test_invalid_open_flags();
+
+        igt_subtest("invalid-oa-metric-set-id")
+                test_invalid_oa_metric_set_id();
+
+        igt_subtest("invalid-oa-format-id")
+                test_invalid_oa_format_id();
+
+        igt_subtest("missing-sample-flags")
+                test_missing_sample_flags();
+
+        igt_subtest("oa-formats")
+                test_oa_formats();
+
+        igt_subtest("invalid-oa-exponent")
+                test_invalid_oa_exponent();
+        igt_subtest("low-oa-exponent-permissions")
+                test_low_oa_exponent_permissions();
+        igt_subtest("oa-exponents") {
+                test_oa_exponents(450);
+                test_oa_exponents(550);
+        }
+
+        igt_subtest("per-context-mode-unprivileged")
+                test_per_context_mode_unprivileged();
+
+        igt_subtest("buffer-fill")
+                test_buffer_fill();
+
+        igt_subtest("disabled-read-error")
+                test_disabled_read_error();
+        igt_subtest("non-sampling-read-error")
+                test_non_sampling_read_error();
+
+        igt_subtest("enable-disable")
+                test_enable_disable();
+
+        igt_subtest("blocking")
+                test_blocking();
+
+        igt_subtest("polling")
+                test_polling();
+
+        igt_subtest("short-reads")
+                test_short_reads();
+
+        igt_subtest("mi-rpc")
+                test_mi_rpc();
+
+        igt_subtest("mi-rpc-per-ctx")
+                test_per_ctx_mi_rpc();
+
+        igt_subtest("i915-ref-count")
+                test_i915_ref_count();
+
+        igt_subtest("rc6-disable")
+                test_rc6_disable();
+
+        igt_fixture {
+                /* leave sysctl options in their default state... */
+                write_u64_file("/proc/sys/dev/i915/oa_max_sample_rate", 100000);
+                write_u64_file("/proc/sys/dev/i915/perf_stream_paranoid", 1);
+
+                gt_frequency_range_restore();
+
+                close(drm_fd);
+        }
+}