diff mbox

[1/9] drm/i915: Add i915 perf infrastructure

Message ID 1461162194-1424-2-git-send-email-robert@sixbynine.org (mailing list archive)
State New, archived
Headers show

Commit Message

Robert Bragg April 20, 2016, 2:23 p.m. UTC
Adds base i915 perf infrastructure for Gen performance metrics.

This adds a DRM_IOCTL_I915_PERF_OPEN ioctl that takes an array of uint64
properties to configure a stream of metrics and returns a new fd usable
with standard VFS system calls including read() to read typed and sized
records; ioctl() to enable or disable capture and poll() to wait for
data.

A stream is opened something like:

  uint64_t properties[] = {
      /* Single context sampling */
      DRM_I915_PERF_PROP_CTX_HANDLE,        ctx_handle,

      /* Include OA reports in samples */
      DRM_I915_PERF_PROP_SAMPLE_OA,         true,

      /* OA unit configuration */
      DRM_I915_PERF_PROP_OA_METRICS_SET,    metrics_set_id,
      DRM_I915_PERF_PROP_OA_FORMAT,         report_format,
      DRM_I915_PERF_PROP_OA_EXPONENT,       period_exponent,
   };
   struct drm_i915_perf_open_param parm = {
      .flags = I915_PERF_FLAG_FD_CLOEXEC |
               I915_PERF_FLAG_FD_NONBLOCK |
               I915_PERF_FLAG_DISABLED,
      .properties_ptr = (uint64_t)properties,
      .num_properties = sizeof(properties) / 16,
   };
   int fd = drmIoctl(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param);

Records read all start with a common { type, size } header with
DRM_I915_PERF_RECORD_SAMPLE being of most interest. Sample records
contain an extensible number of fields and it's the
DRM_I915_PERF_PROP_SAMPLE_xyz properties given when opening that
determine what's included in every sample.

No specific streams are supported yet so any attempt to open a stream
will return an error.

Signed-off-by: Robert Bragg <robert@sixbynine.org>
---
 drivers/gpu/drm/i915/Makefile    |   3 +
 drivers/gpu/drm/i915/i915_dma.c  |   8 +
 drivers/gpu/drm/i915/i915_drv.h  |  86 ++++++++
 drivers/gpu/drm/i915/i915_perf.c | 443 +++++++++++++++++++++++++++++++++++++++
 include/uapi/drm/i915_drm.h      |  67 ++++++
 5 files changed, 607 insertions(+)
 create mode 100644 drivers/gpu/drm/i915/i915_perf.c

Comments

Chris Wilson April 20, 2016, 10:41 p.m. UTC | #1
On Wed, Apr 20, 2016 at 03:23:06PM +0100, Robert Bragg wrote:
> +static struct intel_context *
> +lookup_context(struct drm_i915_private *dev_priv,
> +	       struct file *user_filp,
> +	       u32 ctx_user_handle)
> +{
> +	struct intel_context *ctx;
> +
> +	mutex_lock(&dev_priv->dev->struct_mutex);
> +	list_for_each_entry(ctx, &dev_priv->context_list, link) {
> +		struct drm_file *drm_file;
> +
> +		if (!ctx->file_priv)
> +			continue;
> +
> +		drm_file = ctx->file_priv->file;
> +
> +		if (user_filp->private_data == drm_file &&
> +		    ctx->user_handle == ctx_user_handle) {
> +			i915_gem_context_reference(ctx);
> +			mutex_unlock(&dev_priv->dev->struct_mutex);
> +
> +			return ctx;
> +		}
> +	}
> +	mutex_unlock(&dev_priv->dev->struct_mutex);
> +
> +	return NULL;
> +}
> +
> +int i915_perf_open_ioctl_locked(struct drm_device *dev,
> +				struct drm_i915_perf_open_param *param,
> +				struct perf_open_properties *props,
> +				struct drm_file *file)
> +{
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	struct intel_context *specific_ctx = NULL;
> +	struct i915_perf_stream *stream = NULL;
> +	unsigned long f_flags = 0;
> +	int stream_fd;
> +	int ret = 0;
> +
> +	if (props->single_context) {
> +		u32 ctx_handle = props->ctx_handle;
> +
> +		specific_ctx = lookup_context(dev_priv, file->filp, ctx_handle);

i915_gem_context_get(file->driver_priv, ctx_handle) ?

Though this doesn't allow ptrace like ability to watch a context
elsewhere. For that you need to pass in fd:ctx props.
-Chris
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 0b88ba0..2f7ef71 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -98,6 +98,9 @@  i915-y += dvo_ch7017.o \
 # virtual gpu code
 i915-y += i915_vgpu.o
 
+# perf code
+i915-y += i915_perf.o
+
 # legacy horrors
 i915-y += i915_dma.o
 
diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index b377753..b62e269 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1039,6 +1039,11 @@  static int i915_driver_init_early(struct drm_i915_private *dev_priv,
 	if (ret < 0)
 		return ret;
 
+	/* Must at least be initialized before trying to pin any context
+	 * which i915_perf hooks into.
+	 */
+	i915_perf_init(dev);
+
 	/* This must be called before any calls to HAS_PCH_* */
 	intel_detect_pch(dev);
 
@@ -1425,6 +1430,8 @@  int i915_driver_unload(struct drm_device *dev)
 
 	i915_driver_unregister(dev_priv);
 
+	i915_perf_fini(dev);
+
 	drm_vblank_cleanup(dev);
 
 	intel_modeset_cleanup(dev);
@@ -1579,6 +1586,7 @@  const struct drm_ioctl_desc i915_ioctls[] = {
 	DRM_IOCTL_DEF_DRV(I915_GEM_USERPTR, i915_gem_userptr_ioctl, DRM_RENDER_ALLOW),
 	DRM_IOCTL_DEF_DRV(I915_GEM_CONTEXT_GETPARAM, i915_gem_context_getparam_ioctl, DRM_RENDER_ALLOW),
 	DRM_IOCTL_DEF_DRV(I915_GEM_CONTEXT_SETPARAM, i915_gem_context_setparam_ioctl, DRM_RENDER_ALLOW),
+	DRM_IOCTL_DEF_DRV(I915_PERF_OPEN, i915_perf_open_ioctl, DRM_RENDER_ALLOW),
 };
 
 int i915_max_ioctl = ARRAY_SIZE(i915_ioctls);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 85102ad..5a2a4d6 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1708,6 +1708,79 @@  struct intel_wm_config {
 	bool sprites_scaled;
 };
 
+struct i915_perf_read_state {
+	int count;
+	ssize_t read;
+	char __user *buf;
+};
+
+struct i915_perf_stream {
+	struct drm_i915_private *dev_priv;
+
+	struct list_head link;
+
+	u32 sample_flags;
+
+	struct intel_context *ctx;
+	bool enabled;
+
+	/* Enables the collection of HW samples, either in response to
+	 * I915_PERF_IOCTL_ENABLE or implicitly called when stream is
+	 * opened without I915_PERF_FLAG_DISABLED.
+	 */
+	void (*enable)(struct i915_perf_stream *stream);
+
+	/* Disables the collection of HW samples, either in response to
+	 * I915_PERF_IOCTL_DISABLE or implicitly called before
+	 * destroying the stream.
+	 */
+	void (*disable)(struct i915_perf_stream *stream);
+
+	/* Return: true if any i915 perf records are ready to read()
+	 * for this stream.
+	 */
+	bool (*can_read)(struct i915_perf_stream *stream);
+
+	/* Call poll_wait, passing a wait queue that will be woken
+	 * once there is something ready to read() for the stream
+	 */
+	void (*poll_wait)(struct i915_perf_stream *stream,
+			  struct file *file,
+			  poll_table *wait);
+
+	/* For handling a blocking read, wait until there is something
+	 * to ready to read() for the stream. E.g. wait on the same
+	 * wait queue that would be passed to poll_wait() until
+	 * ->can_read() returns true (if its safe to call ->can_read()
+	 * without the i915 perf lock held).
+	 */
+	int (*wait_unlocked)(struct i915_perf_stream *stream);
+
+	/* Copy as many buffered i915 perf samples and records for
+	 * this stream to userspace as will fit in the given buffer.
+	 *
+	 * Only write complete records.
+	 *
+	 * read_state->count is the length of read_state->buf
+	 *
+	 * Update read_state->read with the number of bytes written.
+	 *
+	 * Return any error condition that results in a short read
+	 * such as -ENOSPC or -EFAULT, even though these may be
+	 * squashed to 0 before returning to userspace (if at least
+	 * one record was successfully copied, as determined via
+	 * the read_state->read length)
+	 */
+	int (*read)(struct i915_perf_stream *stream,
+		    struct i915_perf_read_state *read_state);
+
+	/* Cleanup any stream specific resources.
+	 *
+	 * The stream will always be disabled before this is called.
+	 */
+	void (*destroy)(struct i915_perf_stream *stream);
+};
+
 struct drm_i915_private {
 	struct drm_device *dev;
 	struct kmem_cache *objects;
@@ -1979,6 +2052,12 @@  struct drm_i915_private {
 
 	struct i915_runtime_pm pm;
 
+	struct {
+		bool initialized;
+		struct mutex lock;
+		struct list_head streams;
+	} perf;
+
 	/* Abstract the submission mechanism (legacy ringbuffer or execlists) away */
 	struct {
 		int (*execbuf_submit)(struct i915_execbuffer_params *params,
@@ -3334,6 +3413,9 @@  int i915_gem_context_getparam_ioctl(struct drm_device *dev, void *data,
 int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data,
 				    struct drm_file *file_priv);
 
+int i915_perf_open_ioctl(struct drm_device *dev, void *data,
+			 struct drm_file *file);
+
 /* i915_gem_evict.c */
 int __must_check i915_gem_evict_something(struct drm_device *dev,
 					  struct i915_address_space *vm,
@@ -3450,6 +3532,10 @@  int i915_parse_cmds(struct intel_engine_cs *engine,
 		    u32 batch_len,
 		    bool is_master);
 
+/* i915_perf.c */
+extern void i915_perf_init(struct drm_device *dev);
+extern void i915_perf_fini(struct drm_device *dev);
+
 /* i915_suspend.c */
 extern int i915_save_state(struct drm_device *dev);
 extern int i915_restore_state(struct drm_device *dev);
diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
new file mode 100644
index 0000000..2143401
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -0,0 +1,443 @@ 
+/*
+ * Copyright © 2015 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 <linux/anon_inodes.h>
+#include <linux/sizes.h>
+
+#include "i915_drv.h"
+
+struct perf_open_properties {
+	u32 sample_flags;
+
+	u64 single_context:1;
+	u64 ctx_handle;
+};
+
+static ssize_t i915_perf_read_locked(struct i915_perf_stream *stream,
+				     struct file *file,
+				     char __user *buf,
+				     size_t count,
+				     loff_t *ppos)
+{
+	struct i915_perf_read_state state = { count, 0, buf };
+	int ret = stream->read(stream, &state);
+
+	if ((ret == -ENOSPC || ret == -EFAULT) && state.read)
+		ret = 0;
+
+	if (ret)
+		return ret;
+
+	return state.read ? state.read : -EAGAIN;
+}
+
+static ssize_t i915_perf_read(struct file *file,
+			      char __user *buf,
+			      size_t count,
+			      loff_t *ppos)
+{
+	struct i915_perf_stream *stream = file->private_data;
+	struct drm_i915_private *dev_priv = stream->dev_priv;
+	ssize_t ret;
+
+	if (!(file->f_flags & O_NONBLOCK)) {
+		/* There's the small chance of false positives from
+		 * stream->wait_unlocked.
+		 *
+		 * E.g. with single context filtering since we only wait until
+		 * oabuffer has >= 1 report we don't immediately know whether
+		 * any reports really belong to the current context
+		 */
+		do {
+			ret = stream->wait_unlocked(stream);
+			if (ret)
+				return ret;
+
+			mutex_lock(&dev_priv->perf.lock);
+			ret = i915_perf_read_locked(stream, file,
+						    buf, count, ppos);
+			mutex_unlock(&dev_priv->perf.lock);
+		} while (ret == -EAGAIN);
+	} else {
+		mutex_lock(&dev_priv->perf.lock);
+		ret = i915_perf_read_locked(stream, file, buf, count, ppos);
+		mutex_unlock(&dev_priv->perf.lock);
+	}
+
+	return ret;
+}
+
+static unsigned int i915_perf_poll_locked(struct i915_perf_stream *stream,
+					  struct file *file,
+					  poll_table *wait)
+{
+	unsigned int streams = 0;
+
+	stream->poll_wait(stream, file, wait);
+
+	if (stream->can_read(stream))
+		streams |= POLLIN;
+
+	return streams;
+}
+
+static unsigned int i915_perf_poll(struct file *file, poll_table *wait)
+{
+	struct i915_perf_stream *stream = file->private_data;
+	struct drm_i915_private *dev_priv = stream->dev_priv;
+	int ret;
+
+	mutex_lock(&dev_priv->perf.lock);
+	ret = i915_perf_poll_locked(stream, file, wait);
+	mutex_unlock(&dev_priv->perf.lock);
+
+	return ret;
+}
+
+static void i915_perf_enable_locked(struct i915_perf_stream *stream)
+{
+	if (stream->enabled)
+		return;
+
+	/* Allow stream->enable() to refer to this */
+	stream->enabled = true;
+
+	if (stream->enable)
+		stream->enable(stream);
+}
+
+static void i915_perf_disable_locked(struct i915_perf_stream *stream)
+{
+	if (!stream->enabled)
+		return;
+
+	/* Allow stream->disable() to refer to this */
+	stream->enabled = false;
+
+	if (stream->disable)
+		stream->disable(stream);
+}
+
+static long i915_perf_ioctl_locked(struct i915_perf_stream *stream,
+				   unsigned int cmd,
+				   unsigned long arg)
+{
+	switch (cmd) {
+	case I915_PERF_IOCTL_ENABLE:
+		i915_perf_enable_locked(stream);
+		return 0;
+	case I915_PERF_IOCTL_DISABLE:
+		i915_perf_disable_locked(stream);
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static long i915_perf_ioctl(struct file *file,
+			    unsigned int cmd,
+			    unsigned long arg)
+{
+	struct i915_perf_stream *stream = file->private_data;
+	struct drm_i915_private *dev_priv = stream->dev_priv;
+	long ret;
+
+	mutex_lock(&dev_priv->perf.lock);
+	ret = i915_perf_ioctl_locked(stream, cmd, arg);
+	mutex_unlock(&dev_priv->perf.lock);
+
+	return ret;
+}
+
+static void i915_perf_destroy_locked(struct i915_perf_stream *stream)
+{
+	struct drm_i915_private *dev_priv = stream->dev_priv;
+
+	if (stream->enabled)
+		i915_perf_disable_locked(stream);
+
+	if (stream->destroy)
+		stream->destroy(stream);
+
+	list_del(&stream->link);
+
+	if (stream->ctx) {
+		mutex_lock(&dev_priv->dev->struct_mutex);
+		i915_gem_context_unreference(stream->ctx);
+		mutex_unlock(&dev_priv->dev->struct_mutex);
+	}
+
+	kfree(stream);
+}
+
+static int i915_perf_release(struct inode *inode, struct file *file)
+{
+	struct i915_perf_stream *stream = file->private_data;
+	struct drm_i915_private *dev_priv = stream->dev_priv;
+
+	mutex_lock(&dev_priv->perf.lock);
+	i915_perf_destroy_locked(stream);
+	mutex_unlock(&dev_priv->perf.lock);
+
+	return 0;
+}
+
+
+static const struct file_operations fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= no_llseek,
+	.release	= i915_perf_release,
+	.poll		= i915_perf_poll,
+	.read		= i915_perf_read,
+	.unlocked_ioctl	= i915_perf_ioctl,
+};
+
+static struct intel_context *
+lookup_context(struct drm_i915_private *dev_priv,
+	       struct file *user_filp,
+	       u32 ctx_user_handle)
+{
+	struct intel_context *ctx;
+
+	mutex_lock(&dev_priv->dev->struct_mutex);
+	list_for_each_entry(ctx, &dev_priv->context_list, link) {
+		struct drm_file *drm_file;
+
+		if (!ctx->file_priv)
+			continue;
+
+		drm_file = ctx->file_priv->file;
+
+		if (user_filp->private_data == drm_file &&
+		    ctx->user_handle == ctx_user_handle) {
+			i915_gem_context_reference(ctx);
+			mutex_unlock(&dev_priv->dev->struct_mutex);
+
+			return ctx;
+		}
+	}
+	mutex_unlock(&dev_priv->dev->struct_mutex);
+
+	return NULL;
+}
+
+int i915_perf_open_ioctl_locked(struct drm_device *dev,
+				struct drm_i915_perf_open_param *param,
+				struct perf_open_properties *props,
+				struct drm_file *file)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_context *specific_ctx = NULL;
+	struct i915_perf_stream *stream = NULL;
+	unsigned long f_flags = 0;
+	int stream_fd;
+	int ret = 0;
+
+	if (props->single_context) {
+		u32 ctx_handle = props->ctx_handle;
+
+		specific_ctx = lookup_context(dev_priv, file->filp, ctx_handle);
+		if (!specific_ctx) {
+			DRM_ERROR("Failed to look up context with ID %u for opening perf stream\n",
+				  ctx_handle);
+			ret = -EINVAL;
+			goto err;
+		}
+	}
+
+	if (!specific_ctx && !capable(CAP_SYS_ADMIN)) {
+		DRM_ERROR("Insufficient privileges to open system-wide i915 perf stream\n");
+		ret = -EACCES;
+		goto err_ctx;
+	}
+
+	stream = kzalloc(sizeof(*stream), GFP_KERNEL);
+	if (!stream) {
+		ret = -ENOMEM;
+		goto err_ctx;
+	}
+
+	stream->sample_flags = props->sample_flags;
+	stream->dev_priv = dev_priv;
+	stream->ctx = specific_ctx;
+
+	/*
+	 * TODO: support sampling something
+	 *
+	 * For now this is as far as we can go.
+	 */
+	DRM_ERROR("Unsupported i915 perf stream configuration\n");
+	ret = -EINVAL;
+	goto err_alloc;
+
+	list_add(&stream->link, &dev_priv->perf.streams);
+
+	if (param->flags & I915_PERF_FLAG_FD_CLOEXEC)
+		f_flags |= O_CLOEXEC;
+	if (param->flags & I915_PERF_FLAG_FD_NONBLOCK)
+		f_flags |= O_NONBLOCK;
+
+	stream_fd = anon_inode_getfd("[i915_perf]", &fops, stream, f_flags);
+	if (stream_fd < 0) {
+		ret = stream_fd;
+		goto err_open;
+	}
+
+	if (!(param->flags & I915_PERF_FLAG_DISABLED))
+		i915_perf_enable_locked(stream);
+
+	return stream_fd;
+
+err_open:
+	list_del(&stream->link);
+	if (stream->destroy)
+		stream->destroy(stream);
+err_alloc:
+	kfree(stream);
+err_ctx:
+	if (specific_ctx) {
+		mutex_lock(&dev_priv->dev->struct_mutex);
+		i915_gem_context_unreference(specific_ctx);
+		mutex_unlock(&dev_priv->dev->struct_mutex);
+	}
+err:
+	return ret;
+}
+
+/* Note we copy the properties from userspace outside of the i915 perf
+ * mutex to avoid an awkward lockdep with mmap_sem.
+ *
+ * Note this function only validates properties in isolation it doesn't
+ * validate that the combination of properties makes sense or that all
+ * properties necessary for a particular kind of stream have been set.
+ */
+static int read_properties_unlocked(struct drm_i915_private *dev_priv,
+				    u64 __user *uprops,
+				    u32 n_props,
+				    struct perf_open_properties *props)
+{
+	u64 __user *uprop = uprops;
+	int i;
+
+	memset(props, 0, sizeof(struct perf_open_properties));
+
+	if (!n_props) {
+		DRM_ERROR("No i915 perf properties given");
+		return -EINVAL;
+	}
+
+	if (n_props > DRM_I915_PERF_PROP_MAX) {
+		DRM_ERROR("More i915 perf properties specified than exist");
+		return -EINVAL;
+	}
+
+	for (i = 0; i < n_props; i++) {
+		u64 id, value;
+		int ret;
+
+		ret = get_user(id, (u64 __user *)uprop);
+		if (ret)
+			return ret;
+
+		if (id == 0 || id >= DRM_I915_PERF_PROP_MAX) {
+			DRM_ERROR("Unknown i915 perf property ID");
+			return -EINVAL;
+		}
+
+		ret = get_user(value, (u64 __user *)uprop + 1);
+		if (ret)
+			return ret;
+
+		switch ((enum drm_i915_perf_property_id)id) {
+		case DRM_I915_PERF_PROP_CTX_HANDLE:
+			props->single_context = 1;
+			props->ctx_handle = value;
+			break;
+
+		case DRM_I915_PERF_PROP_MAX:
+			BUG();
+		}
+
+		uprop += 2;
+	}
+
+	return 0;
+}
+
+int i915_perf_open_ioctl(struct drm_device *dev, void *data,
+			 struct drm_file *file)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct drm_i915_perf_open_param *param = data;
+	struct perf_open_properties props;
+	u32 known_open_flags = 0;
+	int ret;
+
+	if (!dev_priv->perf.initialized) {
+		DRM_ERROR("i915 perf interface not available for this system");
+		return -ENOTSUPP;
+	}
+
+	known_open_flags = I915_PERF_FLAG_FD_CLOEXEC |
+			   I915_PERF_FLAG_FD_NONBLOCK |
+			   I915_PERF_FLAG_DISABLED;
+	if (param->flags & ~known_open_flags) {
+		DRM_ERROR("Unknown drm_i915_perf_open_param flag\n");
+		return -EINVAL;
+	}
+
+	ret = read_properties_unlocked(dev_priv,
+				       to_user_ptr(param->properties_ptr),
+				       param->num_properties,
+				       &props);
+	if (ret)
+		return ret;
+
+	mutex_lock(&dev_priv->perf.lock);
+	ret = i915_perf_open_ioctl_locked(dev, param, &props, file);
+	mutex_unlock(&dev_priv->perf.lock);
+
+	return ret;
+}
+
+void i915_perf_init(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = to_i915(dev);
+
+	INIT_LIST_HEAD(&dev_priv->perf.streams);
+	mutex_init(&dev_priv->perf.lock);
+
+	dev_priv->perf.initialized = true;
+}
+
+void i915_perf_fini(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = to_i915(dev);
+
+	if (!dev_priv->perf.initialized)
+		return;
+
+	/* Currently nothing to clean up */
+
+	dev_priv->perf.initialized = false;
+}
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index a5524cc..962cc96 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -230,6 +230,7 @@  typedef struct _drm_i915_sarea {
 #define DRM_I915_GEM_USERPTR		0x33
 #define DRM_I915_GEM_CONTEXT_GETPARAM	0x34
 #define DRM_I915_GEM_CONTEXT_SETPARAM	0x35
+#define DRM_I915_PERF_OPEN		0x36
 
 #define DRM_IOCTL_I915_INIT		DRM_IOW( DRM_COMMAND_BASE + DRM_I915_INIT, drm_i915_init_t)
 #define DRM_IOCTL_I915_FLUSH		DRM_IO ( DRM_COMMAND_BASE + DRM_I915_FLUSH)
@@ -283,6 +284,7 @@  typedef struct _drm_i915_sarea {
 #define DRM_IOCTL_I915_GEM_USERPTR			DRM_IOWR (DRM_COMMAND_BASE + DRM_I915_GEM_USERPTR, struct drm_i915_gem_userptr)
 #define DRM_IOCTL_I915_GEM_CONTEXT_GETPARAM	DRM_IOWR (DRM_COMMAND_BASE + DRM_I915_GEM_CONTEXT_GETPARAM, struct drm_i915_gem_context_param)
 #define DRM_IOCTL_I915_GEM_CONTEXT_SETPARAM	DRM_IOWR (DRM_COMMAND_BASE + DRM_I915_GEM_CONTEXT_SETPARAM, struct drm_i915_gem_context_param)
+#define DRM_IOCTL_I915_PERF_OPEN	DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_PERF_OPEN, struct drm_i915_perf_open_param)
 
 /* Allow drivers to submit batchbuffers directly to hardware, relying
  * on the security mechanisms provided by hardware.
@@ -1170,4 +1172,69 @@  struct drm_i915_gem_context_param {
 	__u64 value;
 };
 
+enum drm_i915_perf_property_id {
+	/**
+	 * Open the stream for a specific context handle (as used with
+	 * execbuffer2). A stream opened for a specific context this way
+	 * won't typically require root privileges.
+	 */
+	DRM_I915_PERF_PROP_CTX_HANDLE = 1,
+
+	DRM_I915_PERF_PROP_MAX /* non-ABI */
+};
+
+struct drm_i915_perf_open_param {
+	__u32 flags;
+#define I915_PERF_FLAG_FD_CLOEXEC	(1<<0)
+#define I915_PERF_FLAG_FD_NONBLOCK	(1<<1)
+#define I915_PERF_FLAG_DISABLED		(1<<2)
+
+	/** The number of u64 (id, value) pairs */
+	__u32 num_properties;
+
+	/**
+	 * Pointer to array of u64 (id, value) pairs configuring the stream
+	 * to open.
+	 */
+	__u64 __user properties_ptr;
+};
+
+#define I915_PERF_IOCTL_ENABLE	_IO('i', 0x0)
+#define I915_PERF_IOCTL_DISABLE	_IO('i', 0x1)
+
+/**
+ * Common to all i915 perf records
+ */
+struct drm_i915_perf_record_header {
+	__u32 type;
+	__u16 pad;
+	__u16 size;
+};
+
+enum drm_i915_perf_record_type {
+
+	/**
+	 * Samples are the work horse record type whose contents are extensible
+	 * and defined when opening an i915 perf stream based on the given
+	 * properties.
+	 *
+	 * Boolean properties following the naming convention
+	 * DRM_I915_PERF_SAMPLE_xyz_PROP request the inclusion of 'xyz' data in
+	 * every sample.
+	 *
+	 * The order of these sample properties given by userspace has no
+	 * affect on the ordering of data within a sample. The order will be
+	 * documented here.
+	 *
+	 * struct {
+	 *     struct drm_i915_perf_record_header header;
+	 *
+	 *     TODO: itemize extensible sample data here
+	 * };
+	 */
+	DRM_I915_PERF_RECORD_SAMPLE = 1,
+
+	DRM_I915_PERF_RECORD_MAX /* non-ABI */
+};
+
 #endif /* _UAPI_I915_DRM_H_ */