diff mbox

[igt] igt: Add gem_ctx_freq to exercise requesting freq on a ctx

Message ID 20180309134659.9594-1-chris@chris-wilson.co.uk (mailing list archive)
State New, archived
Headers show

Commit Message

Chris Wilson March 9, 2018, 1:46 p.m. UTC
Exercise some new API that allows applications to request that
individual contexts are executed within a desired frequency range.

v2: Split single/continuous set_freq subtests
v3: Do an up/down ramp for individual freq request, check nothing
changes after each invalid request

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Paneri, Praveen <praveen.paneri@intel.com>
Cc: Kamble, Sagar A <sagar.a.kamble@intel.com>
Cc: Antonio Argenziano <antonio.argenziano@intel.com>
---
 tests/Makefile.am      |   1 +
 tests/Makefile.sources |   1 +
 tests/gem_ctx_freq.c   | 648 +++++++++++++++++++++++++++++++++++++++++++++++++
 tests/meson.build      |   1 +
 4 files changed, 651 insertions(+)
 create mode 100644 tests/gem_ctx_freq.c

Comments

Tvrtko Ursulin March 9, 2018, 5:06 p.m. UTC | #1
On 09/03/2018 13:46, Chris Wilson wrote:
> Exercise some new API that allows applications to request that
> individual contexts are executed within a desired frequency range.
> 
> v2: Split single/continuous set_freq subtests
> v3: Do an up/down ramp for individual freq request, check nothing
> changes after each invalid request
> 
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Paneri, Praveen <praveen.paneri@intel.com>
> Cc: Kamble, Sagar A <sagar.a.kamble@intel.com>
> Cc: Antonio Argenziano <antonio.argenziano@intel.com>
> ---
>   tests/Makefile.am      |   1 +
>   tests/Makefile.sources |   1 +
>   tests/gem_ctx_freq.c   | 648 +++++++++++++++++++++++++++++++++++++++++++++++++
>   tests/meson.build      |   1 +
>   4 files changed, 651 insertions(+)
>   create mode 100644 tests/gem_ctx_freq.c
> 

[snip]

> +static void check_invalid(int fd, uint32_t ctx, uint32_t min, uint32_t max)
> +{
> +	const struct test {
> +		uint32_t min, max;
> +	} tests[] = {
> +		{ min - 50, max - 50 },
> +		{ min - 50, max },
> +		{ min - 50, max + 50 },
> +		{ min, max + 50 },
> +		{ min + 50, max + 50 },
> +
> +		{ min - 50, min - 50 },
> +
> +		{ min - 50, min },
> +		{ min + 50, min },
> +		{ min, min - 50 },
> +
> +		{ max + 50, max },
> +		{ max, max + 50 },
> +		{ max, max - 50 },
> +
> +		{ max + 50, max + 50 },

Is unprivileged "{ max, max }" allowed? In other words pin to max 
frequency by anyone? If so, what happens when all userspace learns about 
this and wants to use it just so to be lower latency than the other guy?

Or even on our integrated graphics, such userspace would unwisely take 
away power budget from the CPU. Or could it even harm itself by 
triggering too much thermal throttling and run slower than if it let the 
balance be controlled by the system?

Or will this be tied with the cgroup work to allow only clients allowed 
by sysadmin to do this?

Regards,

Tvrtko
Chris Wilson March 9, 2018, 5:24 p.m. UTC | #2
Quoting Tvrtko Ursulin (2018-03-09 17:06:45)
> 
> On 09/03/2018 13:46, Chris Wilson wrote:
> > Exercise some new API that allows applications to request that
> > individual contexts are executed within a desired frequency range.
> > 
> > v2: Split single/continuous set_freq subtests
> > v3: Do an up/down ramp for individual freq request, check nothing
> > changes after each invalid request
> > 
> > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> > Cc: Paneri, Praveen <praveen.paneri@intel.com>
> > Cc: Kamble, Sagar A <sagar.a.kamble@intel.com>
> > Cc: Antonio Argenziano <antonio.argenziano@intel.com>
> > ---
> >   tests/Makefile.am      |   1 +
> >   tests/Makefile.sources |   1 +
> >   tests/gem_ctx_freq.c   | 648 +++++++++++++++++++++++++++++++++++++++++++++++++
> >   tests/meson.build      |   1 +
> >   4 files changed, 651 insertions(+)
> >   create mode 100644 tests/gem_ctx_freq.c
> > 
> 
> [snip]
> 
> > +static void check_invalid(int fd, uint32_t ctx, uint32_t min, uint32_t max)
> > +{
> > +     const struct test {
> > +             uint32_t min, max;
> > +     } tests[] = {
> > +             { min - 50, max - 50 },
> > +             { min - 50, max },
> > +             { min - 50, max + 50 },
> > +             { min, max + 50 },
> > +             { min + 50, max + 50 },
> > +
> > +             { min - 50, min - 50 },
> > +
> > +             { min - 50, min },
> > +             { min + 50, min },
> > +             { min, min - 50 },
> > +
> > +             { max + 50, max },
> > +             { max, max + 50 },
> > +             { max, max - 50 },
> > +
> > +             { max + 50, max + 50 },
> 
> Is unprivileged "{ max, max }" allowed? In other words pin to max 
> frequency by anyone? If so, what happens when all userspace learns about 
> this and wants to use it just so to be lower latency than the other guy?

I've gone with allow, since (a) it's always constrained by the global
user imposed limit and (b) userspace can already keep the gpu at max
frequency by load. At the start I opined that only CAP_SYS_NICE would be
allowed to raise the frequency bounds, but realised that in practice it
is immaterial as they were already running at max frequency anyway.

/*
 * As we constrain the frequency request from the
 * context (application) by the sysadmin imposed limits,
 * it is reasonable to allow the application to
 * specify its preferred range within those limits.
 * That is we do not need to restrict requesting
 * a higher frequency to privileged (CAP_SYS_NICE)
 * processes.
 */

> Or even on our integrated graphics, such userspace would unwisely take 
> away power budget from the CPU. Or could it even harm itself by 
> triggering too much thermal throttling and run slower than if it let the 
> balance be controlled by the system?

It will indeed. Running at max frequency is not a sensible idea for
anything but a few applications (dare we say miners? ;). I thought
compositors might benefit from reduced latency by starting at max,
https://bugs.freedesktop.org/show_bug.cgi?id=102199
but realistically they care more about power consumption and gain most of
the latency reduction from priority sorting and preemption.

On the bright side, we give them a loaded gun with which they can shoot
both feet off. They have to be confident that they do know their
behaviour better than the hw (which for a few will be true). We give
them the means to do so, we do not say it is wise.

> Or will this be tied with the cgroup work to allow only clients allowed 
> by sysadmin to do this?

That's what I think as well. I think we will end up with everything that
can be adjusted via CONTEXT_SETPARAM will be constrained by cgroup.

Once again, we can only look at the integration of schedfreq and CFS as
being the direction the GPUs will also eventually take.
-Chris
diff mbox

Patch

diff --git a/tests/Makefile.am b/tests/Makefile.am
index dbc7be72..389f7fc7 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -104,6 +104,7 @@  drm_import_export_CFLAGS = $(AM_CFLAGS) $(THREAD_CFLAGS)
 drm_import_export_LDADD = $(LDADD) -lpthread
 gem_close_race_CFLAGS = $(AM_CFLAGS) $(THREAD_CFLAGS)
 gem_close_race_LDADD = $(LDADD) -lpthread
+gem_ctx_freq_LDADD = $(LDADD) $(top_builddir)/lib/libigt_perf.la
 gem_ctx_thrash_CFLAGS = $(AM_CFLAGS) $(THREAD_CFLAGS)
 gem_ctx_thrash_LDADD = $(LDADD) -lpthread
 gem_exec_parallel_CFLAGS = $(AM_CFLAGS) $(THREAD_CFLAGS)
diff --git a/tests/Makefile.sources b/tests/Makefile.sources
index 4a81ac4a..3d079c42 100644
--- a/tests/Makefile.sources
+++ b/tests/Makefile.sources
@@ -58,6 +58,7 @@  TESTS_progs = \
 	gem_ctx_bad_exec \
 	gem_ctx_create \
 	gem_ctx_exec \
+	gem_ctx_freq \
 	gem_ctx_isolation \
 	gem_ctx_param \
 	gem_ctx_switch \
diff --git a/tests/gem_ctx_freq.c b/tests/gem_ctx_freq.c
new file mode 100644
index 00000000..f3cee838
--- /dev/null
+++ b/tests/gem_ctx_freq.c
@@ -0,0 +1,648 @@ 
+/*
+ * Copyright © 2018 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 <unistd.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <sys/time.h>
+#include <time.h>
+
+#include "igt.h"
+#include "igt_perf.h"
+
+#define LOCAL_CONTEXT_PARAM_FREQUENCY 7
+
+#define SAMPLE_PERIOD (USEC_PER_SEC / 10)
+
+static int __set_freq(int fd, uint32_t ctx, uint32_t min, uint32_t max)
+{
+	struct drm_i915_gem_context_param param = {
+		.ctx_id = ctx,
+		.param = LOCAL_CONTEXT_PARAM_FREQUENCY,
+		.value = (uint64_t)max << 32 | min,
+	};
+
+	return __gem_context_set_param(fd, &param);
+}
+
+static void set_freq(int fd, uint32_t ctx, uint32_t min, uint32_t max)
+{
+	igt_assert_eq(__set_freq(fd, ctx, min, max), 0);
+}
+
+static void get_freq(int fd, uint32_t ctx, uint32_t *min, uint32_t *max)
+{
+	struct drm_i915_gem_context_param param = {
+		.ctx_id = ctx,
+		.param = LOCAL_CONTEXT_PARAM_FREQUENCY,
+	};
+
+	gem_context_get_param(fd, &param);
+
+	*min = param.value & 0xffffffff;
+	*max = param.value >> 32;
+}
+
+static double measure_frequency(int pmu, int period_us)
+{
+	uint64_t data[2];
+	uint64_t d_t, d_v;
+
+	igt_assert_eq(read(pmu, data, sizeof(data)), sizeof(data));
+	d_v = -data[0];
+	d_t = -data[1];
+
+	usleep(period_us);
+
+	igt_assert_eq(read(pmu, data, sizeof(data)), sizeof(data));
+	d_v += data[0];
+	d_t += data[1];
+
+	return d_v * 1e9 / d_t;
+}
+
+static void single(int fd, const struct intel_execution_engine *e)
+{
+#define N_STEPS 10
+	const unsigned int engine = e->exec_id | e->flags;
+	uint32_t ctx = gem_context_create(fd);
+	uint32_t min, max;
+	double measured;
+	igt_spin_t *spin;
+	int pmu;
+
+	get_freq(fd, ctx, &min, &max);
+	igt_info("Min freq: %dMHz; Max freq: %dMHz\n", min, max);
+
+	pmu = perf_i915_open(I915_PMU_REQUESTED_FREQUENCY);
+	igt_require(pmu >= 0);
+
+	for (int step = 0; step <= 2*N_STEPS; step++) {
+		int frac = step > N_STEPS ? 2*N_STEPS - step : step;
+		uint32_t freq = min + (max - min) * frac / N_STEPS;
+		uint32_t cur, discard;
+
+		set_freq(fd, ctx, freq, freq);
+		get_freq(fd, ctx, &cur, &discard);
+
+		gem_quiescent_gpu(fd);
+		spin = __igt_spin_batch_new(fd, ctx, engine, 0);
+		usleep(10000);
+
+		measured = measure_frequency(pmu, SAMPLE_PERIOD);
+		igt_debugfs_dump(fd, "i915_rps_boost_info");
+
+		igt_spin_batch_free(fd, spin);
+		igt_info("%s(single): Measured %.1fMHz, expected %dMhz\n",
+			 e->name, measured, cur);
+		igt_assert(measured > cur - 100 && measured < cur + 100);
+	}
+	gem_quiescent_gpu(fd);
+
+	close(pmu);
+	gem_context_destroy(fd, ctx);
+
+#undef N_STEPS
+}
+
+static void continuous(int fd, const struct intel_execution_engine *e)
+{
+#define N_STEPS 10
+	const unsigned int engine = e->exec_id | e->flags;
+	uint32_t ctx = gem_context_create(fd);
+	uint32_t min, max;
+	double measured;
+	igt_spin_t *spin;
+	int pmu;
+
+	get_freq(fd, ctx, &min, &max);
+	igt_info("Min freq: %dMHz; Max freq: %dMHz\n", min, max);
+
+	pmu = perf_i915_open(I915_PMU_REQUESTED_FREQUENCY);
+	igt_require(pmu >= 0);
+
+	gem_quiescent_gpu(fd);
+	spin = __igt_spin_batch_new(fd, ctx, engine, 0);
+	for (int step = 0; step <= 2*N_STEPS; step++) {
+		int frac = step > N_STEPS ? 2*N_STEPS - step : step;
+		uint32_t freq = min + (max - min) * frac / N_STEPS;
+		uint32_t cur, discard;
+		igt_spin_t *kick;
+
+		set_freq(fd, ctx, freq, freq);
+		get_freq(fd, ctx, &cur, &discard);
+
+		/*
+		 * When requesting a new frequency on the currently
+		 * executing context, it does not take effect until the
+		 * next context switch. In this case, we trigger a lite
+		 * restore.
+		 */
+		kick = __igt_spin_batch_new(fd, ctx, engine, 0);
+		igt_spin_batch_free(fd, spin);
+		spin = kick;
+
+		usleep(10000);
+
+		measured = measure_frequency(pmu, SAMPLE_PERIOD);
+		igt_debugfs_dump(fd, "i915_rps_boost_info");
+
+		igt_info("%s(continuous): Measured %.1fMHz, expected %dMhz\n",
+			 e->name, measured, cur);
+		igt_assert(measured > cur - 100 && measured < cur + 100);
+	}
+	igt_spin_batch_free(fd, spin);
+	gem_quiescent_gpu(fd);
+
+	close(pmu);
+	gem_context_destroy(fd, ctx);
+#undef N_STEPS
+}
+
+static void inflight(int fd, const struct intel_execution_engine *e)
+{
+	const unsigned int engine = e->exec_id | e->flags;
+	uint32_t ctx, min, max, freq, discard;
+	double measured;
+	igt_spin_t *plug, *work[2];
+	int pmu;
+
+	pmu = perf_i915_open(I915_PMU_REQUESTED_FREQUENCY);
+	igt_require(pmu >= 0);
+
+	ctx = gem_context_create(fd);
+	get_freq(fd, ctx, &min, &max);
+	set_freq(fd, ctx, min, min);
+
+	igt_info("Min freq: %dMHz; Max freq: %dMHz\n", min, max);
+
+	gem_quiescent_gpu(fd);
+	plug = igt_spin_batch_new(fd, ctx, engine, 0);
+	gem_context_destroy(fd, ctx);
+	for (int n = 0; n < 16; n++) {
+		struct drm_i915_gem_exec_object2 obj = {
+			.handle = plug->handle,
+		};
+		struct drm_i915_gem_execbuffer2 eb = {
+			.buffer_count = 1,
+			.buffers_ptr = to_user_pointer(&obj),
+			.flags = engine,
+			.rsvd1 = gem_context_create(fd),
+		};
+		set_freq(fd, eb.rsvd1, min, min);
+		gem_execbuf(fd, &eb);
+		gem_context_destroy(fd, eb.rsvd1);
+	}
+	measured = measure_frequency(pmu, SAMPLE_PERIOD);
+	igt_debugfs_dump(fd, "i915_rps_boost_info");
+	igt_info("%s(plug): Measured %.1fMHz, expected %dMhz\n",
+		 e->name, measured, min);
+	igt_assert(measured > min - 100 && measured < min + 100);
+
+	ctx = gem_context_create(fd);
+	set_freq(fd, ctx, max, max);
+	work[0] = __igt_spin_batch_new(fd, ctx, engine, 0);
+
+	/* work is now queued but not executing */
+	freq = (max + min) / 2;
+	set_freq(fd, ctx, freq, freq);
+	get_freq(fd, ctx, &freq, &discard);
+	gem_context_destroy(fd, ctx);
+
+	ctx = gem_context_create(fd);
+	set_freq(fd, ctx, max, max);
+	work[1] = __igt_spin_batch_new(fd, ctx, engine, 0);
+	gem_context_destroy(fd, ctx);
+
+	igt_spin_batch_end(plug);
+	do
+		usleep(10000);
+	while (gem_bo_busy(fd, plug->handle));
+	igt_spin_batch_free(fd, plug);
+
+	/* Now work will execute */
+	measured = measure_frequency(pmu, SAMPLE_PERIOD);
+	igt_debugfs_dump(fd, "i915_engine_info");
+	igt_debugfs_dump(fd, "i915_rps_boost_info");
+	igt_info("%s(work0): Measured %.1fMHz, expected %dMhz\n",
+		 e->name, measured, freq);
+	igt_assert(measured > freq - 100 && measured < freq + 100);
+
+	igt_spin_batch_end(work[0]);
+	do
+		usleep(10000);
+	while (gem_bo_busy(fd, work[0]->handle));
+	igt_spin_batch_free(fd, work[0]);
+
+	measured = measure_frequency(pmu, SAMPLE_PERIOD);
+	igt_debugfs_dump(fd, "i915_engine_info");
+	igt_debugfs_dump(fd, "i915_rps_boost_info");
+	igt_info("%s(work1): Measured %.1fMHz, expected %dMhz\n",
+		 e->name, measured, max);
+	igt_assert(measured > max - 100 && measured < max + 100);
+
+	igt_spin_batch_free(fd, work[1]);
+	close(pmu);
+	gem_quiescent_gpu(fd);
+}
+
+static void sandwich(int fd)
+{
+	uint32_t ctx = gem_context_create(fd);
+	unsigned int engine;
+	uint32_t min, max;
+	igt_spin_t *spin;
+	int pmu;
+
+	pmu = perf_i915_open(I915_PMU_REQUESTED_FREQUENCY);
+	igt_require(pmu >= 0);
+
+	spin = igt_spin_batch_new(fd, ctx, 0, 0);
+	get_freq(fd, ctx, &min, &max);
+	set_freq(fd, ctx, min, min);
+	for_each_physical_engine(fd, engine) {
+		struct drm_i915_gem_exec_object2 obj = {
+			.handle = spin->handle,
+		};
+		struct drm_i915_gem_execbuffer2 eb = {
+			.buffer_count = 1,
+			.buffers_ptr = to_user_pointer(&obj),
+			.flags = engine,
+			.rsvd1 = ctx,
+		};
+		uint32_t cur, discard;
+		double measured;
+
+		min += 50;
+		if (min > max)
+			break;
+
+		set_freq(fd, ctx, min, min);
+		get_freq(fd, ctx, &cur, &discard);
+
+		gem_execbuf(fd, &eb);
+		usleep(10000);
+
+		measured = measure_frequency(pmu, SAMPLE_PERIOD);
+		igt_debugfs_dump(fd, "i915_rps_boost_info");
+
+		igt_info("Measured %.1fMHz, expected %dMhz\n", measured, cur);
+		igt_assert(measured > cur - 100 && measured < cur + 100);
+	}
+	igt_spin_batch_free(fd, spin);
+	gem_quiescent_gpu(fd);
+
+	gem_context_destroy(fd, ctx);
+	close(pmu);
+}
+
+static void pwm(int fd, unsigned int *engines, unsigned int nengine, int link)
+{
+	uint32_t ctx[nengine];
+
+	fcntl(link, F_SETFL, fcntl(fd, F_GETFL) | O_NONBLOCK);
+
+	for (unsigned int n = 0; n < nengine; n++)
+		ctx[n] = gem_context_create(fd);
+
+	do {
+		igt_spin_t *spin;
+		struct {
+			uint32_t engine;
+			uint32_t min;
+			uint32_t max;
+		} req;
+
+		while (read(link, &req, sizeof(req)) > 0) {
+			if ((req.engine | req.min | req.max) == 0)
+				goto out;
+
+			igt_assert(req.engine < nengine);
+			set_freq(fd, ctx[req.engine], req.min, req.max);
+		}
+
+		/* Create a 20% load using busy spinners */
+		spin = __igt_spin_batch_new(fd, ctx[0], engines[0], 0);
+		for (unsigned int n = 1; n < nengine; n++) {
+			struct drm_i915_gem_exec_object2 obj = {
+				.handle = spin->handle,
+			};
+			struct drm_i915_gem_execbuffer2 eb = {
+				.buffer_count = 1,
+				.buffers_ptr = to_user_pointer(&obj),
+				.flags = engines[n],
+				.rsvd1 = ctx[n],
+			};
+			gem_execbuf(fd, &eb);
+		}
+		usleep(100);
+		igt_spin_batch_end(spin);
+
+		do
+			usleep(10);
+		while (gem_bo_busy(fd, spin->handle));
+		igt_spin_batch_free(fd, spin);
+		usleep(400);
+	} while (1);
+
+out:
+	for (unsigned int n = 0; n < nengine; n++)
+		gem_context_destroy(fd, ctx[n]);
+}
+
+static void smoketest(int fd, int timeout)
+{
+	unsigned int engines[16];
+	unsigned int nengine;
+	unsigned int engine;
+	uint32_t min[16], max[16];
+	int pmu, link[2];
+
+	get_freq(fd, 0, &min[0], &max[0]);
+
+	nengine = 0;
+	for_each_physical_engine(fd, engine) {
+		if (nengine == ARRAY_SIZE(engines) - 1)
+			break;
+
+		min[nengine] = min[0];
+		max[nengine] = max[0];
+		engines[nengine] = engine;
+		nengine++;
+	}
+	igt_require(nengine);
+
+	igt_assert(pipe(link) == 0);
+	igt_fork(child, 1)
+		pwm(fd, engines, nengine, link[0]);
+	close(link[0]);
+
+	pmu = perf_i915_open(I915_PMU_REQUESTED_FREQUENCY);
+	igt_require(pmu >= 0);
+
+	igt_until_timeout(timeout) {
+		struct {
+			uint32_t engine;
+			uint32_t min;
+			uint32_t max;
+		} req;
+		double measured;
+		uint32_t ctx;
+
+		req.engine = rand() % nengine;
+
+		ctx = gem_context_create(fd);
+		get_freq(fd, ctx, &req.min, &req.max);
+		req.min = rand() % (req.max - req.min) + req.min;
+		req.max = rand() % (req.max - req.min) + req.min;
+		set_freq(fd, ctx, req.min, req.max);
+		get_freq(fd, ctx, &req.min, &req.max);
+
+		igt_debug("Replacing (%d, %d) on engine %x with (%d, %d)\n",
+			  min[req.engine], max[req.engine], req.engine,
+			  req.min, req.max);
+		igt_assert(write(link[1], &req, sizeof(req)) == sizeof(req));
+		gem_context_destroy(fd, ctx);
+
+		min[req.engine] = req.min;
+		max[req.engine] = req.max;
+
+		for (unsigned int n = 0; n < nengine; n++) {
+			igt_debug("[%d]: [%d, %d]\n", n, min[n], max[n]);
+			if (min[n] < req.min)
+				req.min = min[n];
+			if (max[n] > req.max)
+				req.max = max[n];
+		}
+		igt_assert(req.max >= req.min);
+
+		usleep(50000);
+		measured = measure_frequency(pmu, SAMPLE_PERIOD);
+
+		if (measured <= req.min - 100 || measured >= req.max + 100)
+			igt_debugfs_dump(fd, "i915_rps_boost_info");
+		igt_info("Measured %.1fMHz, expected [%d, %d]Mhz\n",
+			 measured, req.min, req.max);
+		igt_assert(measured > req.min - 100 &&
+			   measured < req.max + 100);
+	}
+
+	do {
+		struct {
+			uint32_t engine;
+			uint32_t min;
+			uint32_t max;
+		} req = {};
+
+		write(link[1], &req, sizeof(req));
+		close(link[1]);
+	} while (0);
+	igt_waitchildren();
+	gem_quiescent_gpu(fd);
+
+	close(pmu);
+}
+
+static void check_invalid(int fd, uint32_t ctx, uint32_t min, uint32_t max)
+{
+	const struct test {
+		uint32_t min, max;
+	} tests[] = {
+		{ min - 50, max - 50 },
+		{ min - 50, max },
+		{ min - 50, max + 50 },
+		{ min, max + 50 },
+		{ min + 50, max + 50 },
+
+		{ min - 50, min - 50 },
+
+		{ min - 50, min },
+		{ min + 50, min },
+		{ min, min - 50 },
+
+		{ max + 50, max },
+		{ max, max + 50 },
+		{ max, max - 50 },
+
+		{ max + 50, max + 50 },
+
+		{}
+	};
+
+	for (const struct test *t = tests; t->min | t->max; t++) {
+		uint32_t cur_min, cur_max;
+
+		igt_assert_f(__set_freq(fd, ctx, t->min, t->max) == -EINVAL,
+			     "Failed to reject invalid [%d, %d] (valid range [%d, %d]) on context %d\n",
+			     t->min, t->max, min, max, ctx);
+
+		get_freq(fd, 0, &cur_min, &cur_max);
+		igt_assert_eq(cur_min, min);
+		igt_assert_eq(cur_max, max);
+	}
+}
+
+static void invalid_param(int fd)
+{
+	uint32_t min, max, ctx;
+
+	get_freq(fd, 0, &min, &max);
+
+	check_invalid(fd, 0, min, max);
+
+	ctx = gem_context_create(fd);
+	check_invalid(fd, ctx, min, max);
+	gem_context_destroy(fd, ctx);
+}
+
+static void idempotent(int fd)
+{
+	uint32_t min, max;
+	uint32_t cur_min, cur_max;
+
+	get_freq(fd, 0, &min, &max);
+
+	set_freq(fd, 0, max, max);
+	get_freq(fd, 0, &cur_min, &cur_max);
+	igt_assert_eq(cur_min, max);
+	igt_assert_eq(cur_max, max);
+
+	set_freq(fd, 0, min, min);
+	get_freq(fd, 0, &cur_min, &cur_max);
+	igt_assert_eq(cur_min, min);
+	igt_assert_eq(cur_max, min);
+
+	set_freq(fd, 0, min, max);
+	get_freq(fd, 0, &cur_min, &cur_max);
+	igt_assert_eq(cur_min, min);
+	igt_assert_eq(cur_max, max);
+}
+
+static void independent(int fd)
+{
+	uint32_t min, max;
+	uint32_t cur_min, cur_max;
+	uint32_t ctx[2];
+
+	get_freq(fd, 0, &min, &max);
+
+	set_freq(fd, 0, max, max);
+	ctx[0] = gem_context_create(fd);
+	get_freq(fd, ctx[0], &cur_min, &cur_max);
+	igt_assert_eq(cur_min, min);
+	igt_assert_eq(cur_max, max);
+
+	set_freq(fd, 0, min, min);
+	get_freq(fd, ctx[0], &cur_min, &cur_max);
+	igt_assert_eq(cur_min, min);
+	igt_assert_eq(cur_max, max);
+
+	ctx[1] = gem_context_create(fd);
+	get_freq(fd, ctx[1], &cur_min, &cur_max);
+	igt_assert_eq(cur_min, min);
+	igt_assert_eq(cur_max, max);
+
+	set_freq(fd, ctx[1], max, max);
+	get_freq(fd, ctx[0], &cur_min, &cur_max);
+	igt_assert_eq(cur_min, min);
+	igt_assert_eq(cur_max, max);
+
+	get_freq(fd, 0, &cur_min, &cur_max);
+	igt_assert_eq(cur_min, min);
+	igt_assert_eq(cur_max, min);
+
+	get_freq(fd, ctx[1], &cur_min, &cur_max);
+	igt_assert_eq(cur_min, max);
+	igt_assert_eq(cur_max, max);
+	gem_context_destroy(fd, ctx[1]);
+
+	get_freq(fd, ctx[0], &cur_min, &cur_max);
+	igt_assert_eq(cur_min, min);
+	igt_assert_eq(cur_max, max);
+	gem_context_destroy(fd, ctx[0]);
+}
+
+static bool has_ctx_freq(int fd)
+{
+	struct drm_i915_gem_context_param param = {
+		.param = LOCAL_CONTEXT_PARAM_FREQUENCY,
+	};
+
+	return __gem_context_get_param(fd, &param) == 0;
+}
+
+igt_main
+{
+	const struct intel_execution_engine *e;
+	int fd = -1;
+
+	igt_fixture {
+		fd = drm_open_driver(DRIVER_INTEL);
+		igt_require_gem(fd);
+
+		igt_require(has_ctx_freq(fd));
+	}
+
+	igt_subtest("invalid")
+		invalid_param(fd);
+
+	igt_subtest("idempotent")
+		idempotent(fd);
+
+	igt_subtest("independent")
+		independent(fd);
+
+	igt_skip_on_simulation();
+
+	for (e = intel_execution_engines; e->name; e++) {
+		if (e->exec_id == 0)
+			continue;
+
+		igt_subtest_group {
+			igt_fixture {
+				igt_require(gem_ring_has_physical_engine(fd, e->exec_id | e->flags));
+			}
+
+			igt_subtest_f("%s-single", e->name)
+				single(fd, e);
+			igt_subtest_f("%s-continuous", e->name)
+				continuous(fd, e);
+			igt_subtest_f("%s-inflight", e->name)
+				inflight(fd, e);
+		}
+	}
+
+	igt_subtest("sandwich")
+		sandwich(fd);
+
+	igt_subtest("smoketest")
+		smoketest(fd, 20);
+}
diff --git a/tests/meson.build b/tests/meson.build
index 6e776bb7..fa5e3169 100644
--- a/tests/meson.build
+++ b/tests/meson.build
@@ -36,6 +36,7 @@  test_progs = [
 	'gem_ctx_create',
 	'gem_ctx_exec',
 	'gem_ctx_isolation',
+	'gem_ctx_freq',
 	'gem_ctx_param',
 	'gem_ctx_switch',
 	'gem_ctx_thrash',