[Intel-gfx] [RFC 1/6] drm/i915: Add i915 perf infrastructure

Robert Bragg robert at sixbynine.org
Tue Sep 29 07:39:04 PDT 2015


This adds a DRM_IOCTL_I915_PERF_OPEN ioctl comparable to perf_event_open
that opens a file descriptor for an event source.

Based on our initial experience aiming to use the core perf
infrastructure, this interface is inspired by perf, but focused on
exposing metrics about work running on Gen graphics instead a CPU.

One notable difference is that it doesn't support mmaping a circular
buffer of samples into userspace. The currently planned use cases
require an internal buffering that forces at least one copy of data
which can be neatly hidden in a read() based interface.

No specific event types are supported yet so perf_event_open can currently
only get as far as returning EINVAL for an unknown event type.

Signed-off-by: Robert Bragg <robert at sixbynine.org>
---
 drivers/gpu/drm/i915/Makefile    |   3 +
 drivers/gpu/drm/i915/i915_dma.c  |   7 +
 drivers/gpu/drm/i915/i915_drv.h  |  74 +++++++
 drivers/gpu/drm/i915/i915_perf.c | 447 +++++++++++++++++++++++++++++++++++++++
 include/uapi/drm/i915_drm.h      |  62 ++++++
 5 files changed, 593 insertions(+)
 create mode 100644 drivers/gpu/drm/i915/i915_perf.c

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 44d290a..5485495 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -93,6 +93,9 @@ 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 2193cc2..0424e8c 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -841,6 +841,11 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
 	mutex_init(&dev_priv->modeset_restore_lock);
 	mutex_init(&dev_priv->csr_lock);
 
+	/* Must at least be initialized before trying to pin any context
+	 * which i915_perf hooks into.
+	 */
+	i915_perf_init(dev);
+
 	intel_pm_setup(dev);
 
 	intel_display_crc_init(dev);
@@ -1090,6 +1095,7 @@ int i915_driver_unload(struct drm_device *dev)
 		return ret;
 	}
 
+	i915_perf_fini(dev);
 	intel_power_domains_fini(dev_priv);
 
 	intel_gpu_ips_teardown();
@@ -1280,6 +1286,7 @@ const struct drm_ioctl_desc i915_ioctls[] = {
 	DRM_IOCTL_DEF_DRV(I915_GEM_USERPTR, i915_gem_userptr_ioctl, DRM_UNLOCKED|DRM_RENDER_ALLOW),
 	DRM_IOCTL_DEF_DRV(I915_GEM_CONTEXT_GETPARAM, i915_gem_context_getparam_ioctl, DRM_UNLOCKED|DRM_RENDER_ALLOW),
 	DRM_IOCTL_DEF_DRV(I915_GEM_CONTEXT_SETPARAM, i915_gem_context_setparam_ioctl, DRM_UNLOCKED|DRM_RENDER_ALLOW),
+	DRM_IOCTL_DEF_DRV(I915_PERF_OPEN, i915_perf_open_ioctl, DRM_UNLOCKED|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 e0f3f05..c16c9e5 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1694,6 +1694,67 @@ struct i915_execbuffer_params {
 	struct drm_i915_gem_request     *request;
 };
 
+struct i915_perf_read_state {
+	int count;
+	ssize_t read;
+	char __user *buf;
+};
+
+struct i915_perf_event {
+	struct drm_i915_private *dev_priv;
+
+	struct list_head link;
+
+	u32 sample_flags;
+
+	struct intel_context *ctx;
+	bool enabled;
+
+	/* Enables the collection of HW events, either in response to
+	 * I915_PERF_IOCTL_ENABLE or implicitly called when event is
+	 * opened without I915_PERF_FLAG_DISABLED */
+	void (*enable)(struct i915_perf_event *event);
+
+	/* Disables the collection of HW events, either in response to
+	 * I915_PERF_IOCTL_DISABLE or implicitly called before
+	 * destroying the event. */
+	void (*disable)(struct i915_perf_event *event);
+
+	/* Return: true if any i915 perf records are ready to read()
+	 * for this event */
+	bool (*can_read)(struct i915_perf_event *event);
+
+	/* Call poll_wait, passing a wait queue that will be woken
+	 * once there is something to ready to read() for the event */
+	void (*poll_wait)(struct i915_perf_event *event,
+			  struct file *file,
+			  poll_table *wait);
+
+	/* For handling a blocking read, wait until there is something
+	 * to ready to read() for the event. 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_event *event);
+
+	/* Copy as many buffered i915 perf samples and records for
+	 * this event 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.
+	 */
+	void (*read)(struct i915_perf_event *event,
+		     struct i915_perf_read_state *read_state);
+
+	/* Cleanup any event specific resources.
+	 *
+	 * The event will always be disabled before this is called */
+	void (*destroy)(struct i915_perf_event *event);
+};
+
 struct drm_i915_private {
 	struct drm_device *dev;
 	struct kmem_cache *objects;
@@ -1928,6 +1989,12 @@ struct drm_i915_private {
 
 	struct i915_runtime_pm pm;
 
+	struct {
+		bool initialized;
+		struct mutex lock;
+		struct list_head events;
+	} perf;
+
 	/* Abstract the submission mechanism (legacy ringbuffer or execlists) away */
 	struct {
 		int (*execbuf_submit)(struct i915_execbuffer_params *params,
@@ -3130,6 +3197,9 @@ 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,
@@ -3239,6 +3309,10 @@ int i915_parse_cmds(struct intel_engine_cs *ring,
 		    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..477e3e6
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -0,0 +1,447 @@
+/*
+ * 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/perf_event.h>
+#include <linux/anon_inodes.h>
+#include <linux/sizes.h>
+
+#include "i915_drv.h"
+
+/**
+ * i915_perf_copy_attr() - copy specific event attributes from userspace
+ * @uattr:	The u64 __user attr of drm_i915_perf_open_param
+ * @attr:	Destination for copied attributes
+ * @v0_size:	The smallest, version 0 size of these attributes
+ * @real_size:	The latest size expected by this kernel version
+ *
+ * Specific events can define a custom attributes structure and for
+ * consistency should use this utility for reading the attributes from
+ * userspace.
+ *
+ * Note: although this verifies any unknown members beyond the expected
+ * struct size are zeroed it can't check for unused flags
+ *
+ * Return: 0 if successful, else an error code
+ */
+static int i915_perf_copy_attr(void __user *uattr,
+			       void *attr,
+			       u32 v0_size,
+			       u32 real_size)
+{
+	u32 size;
+	int ret;
+
+	if (!access_ok(VERIFY_WRITE, uattr, v0_size))
+		return -EFAULT;
+
+	/*
+	 * zero the full structure, so that a short copy will be nice.
+	 */
+	memset(attr, 0, real_size);
+
+	ret = get_user(size, (u32 __user *)uattr);
+	if (ret)
+		return ret;
+
+	if (size > PAGE_SIZE)   /* silly large */
+		goto err_size;
+
+	if (size < v0_size)
+		goto err_size;
+
+	/*
+	 * If we're handed a bigger struct than we know of,
+	 * ensure all the unknown bits are 0 - i.e. new
+	 * user-space does not rely on any kernel feature
+	 * extensions we dont know about yet.
+	 */
+
+	if (size > real_size) {
+		unsigned char __user *addr;
+		unsigned char __user *end;
+		unsigned char val;
+
+		addr = (void __user *)uattr + sizeof(*attr);
+		end  = (void __user *)uattr + size;
+
+		for (; addr < end; addr++) {
+			ret = get_user(val, addr);
+			if (ret)
+				return ret;
+			if (val)
+				goto err_size;
+		}
+		size = sizeof(*attr);
+	}
+
+	ret = copy_from_user(attr, uattr, size);
+	if (ret)
+		return -EFAULT;
+
+out:
+	return ret;
+
+err_size:
+	put_user(real_size, (u32 __user *)uattr);
+	ret = -E2BIG;
+	goto out;
+}
+
+static ssize_t i915_perf_read_locked(struct i915_perf_event *event,
+				     struct file *file,
+				     char __user *buf,
+				     size_t count,
+				     loff_t *ppos)
+{
+	struct drm_i915_private *dev_priv = event->dev_priv;
+	struct i915_perf_read_state state = { count, 0, buf };
+	int ret;
+
+	if (file->f_flags & O_NONBLOCK) {
+		if (!event->can_read(event))
+			return -EAGAIN;
+	} else {
+		mutex_unlock(&dev_priv->perf.lock);
+		ret = event->wait_unlocked(event);
+		mutex_lock(&dev_priv->perf.lock);
+
+		if (ret)
+			return ret;
+	}
+
+	event->read(event, &state);
+	if (state.read == 0)
+		return -ENOSPC;
+
+	return state.read;
+}
+
+static ssize_t i915_perf_read(struct file *file,
+			      char __user *buf,
+			      size_t count,
+			      loff_t *ppos)
+{
+	struct i915_perf_event *event = file->private_data;
+	struct drm_i915_private *dev_priv = event->dev_priv;
+	ssize_t ret;
+
+	mutex_lock(&dev_priv->perf.lock);
+	ret = i915_perf_read_locked(event, file, buf, count, ppos);
+	mutex_unlock(&dev_priv->perf.lock);
+
+	return ret;
+}
+
+static unsigned int i915_perf_poll_locked(struct i915_perf_event *event,
+					  struct file *file,
+					  poll_table *wait)
+{
+	unsigned int events = 0;
+
+	event->poll_wait(event, file, wait);
+
+	if (event->can_read(event))
+		events |= POLLIN;
+
+	return events;
+}
+
+static unsigned int i915_perf_poll(struct file *file, poll_table *wait)
+{
+	struct i915_perf_event *event = file->private_data;
+	struct drm_i915_private *dev_priv = event->dev_priv;
+	int ret;
+
+	mutex_lock(&dev_priv->perf.lock);
+	ret = i915_perf_poll_locked(event, file, wait);
+	mutex_unlock(&dev_priv->perf.lock);
+
+	return ret;
+}
+
+static void i915_perf_enable_locked(struct i915_perf_event *event)
+{
+	if (event->enabled)
+		return;
+
+	/* Allow event->enable() to refer to this */
+	event->enabled = true;
+
+	if (event->enable)
+		event->enable(event);
+}
+
+static void i915_perf_disable_locked(struct i915_perf_event *event)
+{
+	if (!event->enabled)
+		return;
+
+	/* Allow event->disable() to refer to this */
+	event->enabled = false;
+
+	if (event->disable)
+		event->disable(event);
+}
+
+static long i915_perf_ioctl_locked(struct i915_perf_event *event,
+				   unsigned int cmd,
+				   unsigned long arg)
+{
+	switch (cmd) {
+	case I915_PERF_IOCTL_ENABLE:
+		i915_perf_enable_locked(event);
+		return 0;
+	case I915_PERF_IOCTL_DISABLE:
+		i915_perf_disable_locked(event);
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static long i915_perf_ioctl(struct file *file,
+			    unsigned int cmd,
+			    unsigned long arg)
+{
+	struct i915_perf_event *event = file->private_data;
+	struct drm_i915_private *dev_priv = event->dev_priv;
+	long ret;
+
+	mutex_lock(&dev_priv->perf.lock);
+	ret = i915_perf_ioctl_locked(event, cmd, arg);
+	mutex_unlock(&dev_priv->perf.lock);
+
+	return ret;
+}
+
+static void i915_perf_destroy_locked(struct i915_perf_event *event)
+{
+	struct drm_i915_private *dev_priv = event->dev_priv;
+
+	if (event->enabled)
+		i915_perf_disable_locked(event);
+
+	if (event->destroy)
+		event->destroy(event);
+
+	list_del(&event->link);
+
+	if (event->ctx) {
+		mutex_lock(&dev_priv->dev->struct_mutex);
+		i915_gem_context_unreference(event->ctx);
+		mutex_unlock(&dev_priv->dev->struct_mutex);
+	}
+
+	kfree(event);
+}
+
+static int i915_perf_release(struct inode *inode, struct file *file)
+{
+	struct i915_perf_event *event = file->private_data;
+	struct drm_i915_private *dev_priv = event->dev_priv;
+
+	mutex_lock(&dev_priv->perf.lock);
+	i915_perf_destroy_locked(event);
+	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, void *data,
+				struct drm_file *file)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct drm_i915_perf_open_param *param = data;
+	u32 known_open_flags = 0;
+	u64 known_sample_flags = 0;
+	struct intel_context *specific_ctx = NULL;
+	struct i915_perf_event *event = NULL;
+	unsigned long f_flags = 0;
+	int event_fd;
+	int ret = 0;
+
+	known_open_flags = I915_PERF_FLAG_FD_CLOEXEC |
+			   I915_PERF_FLAG_FD_NONBLOCK |
+			   I915_PERF_FLAG_SINGLE_CONTEXT |
+			   I915_PERF_FLAG_DISABLED;
+	if (param->flags & ~known_open_flags) {
+		DRM_ERROR("Unknown drm_i915_perf_open_param flag\n");
+		ret = -EINVAL;
+		goto err;
+	}
+
+	known_sample_flags = I915_PERF_SAMPLE_OA_REPORT |
+			     I915_PERF_SAMPLE_CTXID |
+			     I915_PERF_SAMPLE_TIMESTAMP;
+	if (param->sample_flags & ~known_sample_flags) {
+		DRM_ERROR("Unknown drm_i915_perf_open_param sample_flag\n");
+		ret = -EINVAL;
+		goto err;
+	}
+
+	if (param->flags & I915_PERF_FLAG_SINGLE_CONTEXT) {
+		u32 ctx_id = param->ctx_id;
+
+		specific_ctx = lookup_context(dev_priv, file->filp, ctx_id);
+		if (!specific_ctx) {
+			DRM_ERROR("Failed to look up context with ID %u for opening perf event\n", ctx_id);
+			ret = -EINVAL;
+			goto err;
+		}
+	}
+
+	if (!specific_ctx && !capable(CAP_SYS_ADMIN)) {
+		DRM_ERROR("Insufficient privileges to open perf event\n");
+		ret = -EACCES;
+		goto err_ctx;
+	}
+
+	event = kzalloc(sizeof(*event), GFP_KERNEL);
+	if (!event) {
+		ret = -ENOMEM;
+		goto err_ctx;
+	}
+
+	event->sample_flags = param->sample_flags;
+	event->dev_priv = dev_priv;
+	event->ctx = specific_ctx;
+
+	switch (param->type) {
+		/* TODO: Init according to specific type */
+	default:
+		DRM_ERROR("Unknown perf event type\n");
+		ret = -EINVAL;
+		goto err_alloc;
+	}
+
+	event->ctx = specific_ctx;
+	list_add(&event->link, &dev_priv->perf.events);
+
+	if (param->flags & I915_PERF_FLAG_FD_CLOEXEC)
+		f_flags |= O_CLOEXEC;
+	if (param->flags & I915_PERF_FLAG_FD_NONBLOCK)
+		f_flags |= O_NONBLOCK;
+
+	event_fd = anon_inode_getfd("[i915_perf]", &fops, event, f_flags);
+	if (event_fd < 0) {
+		ret = event_fd;
+		goto err_open;
+	}
+
+	param->fd = event_fd;
+
+	if (!(param->flags & I915_PERF_FLAG_DISABLED))
+		i915_perf_enable_locked(event);
+
+	return 0;
+
+err_open:
+	list_del(&event->link);
+	if (event->destroy)
+		event->destroy(event);
+err_alloc:
+	kfree(event);
+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:
+	param->fd = -1;
+
+	return ret;
+}
+
+int i915_perf_open_ioctl(struct drm_device *dev, void *data,
+			    struct drm_file *file)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	int ret;
+
+	mutex_lock(&dev_priv->perf.lock);
+	ret = i915_perf_open_ioctl_locked(dev, data, 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);
+
+	/* Currently no global event state to initialize */
+
+	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 dbd16a2..a84f71f 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.
@@ -1129,4 +1131,64 @@ struct drm_i915_gem_context_param {
 	__u64 value;
 };
 
+enum drm_i915_perf_event_type {
+	I915_PERF_EVENT_TYPE_MAX	/* non-ABI */
+};
+
+#define I915_PERF_FLAG_FD_CLOEXEC	(1<<0)
+#define I915_PERF_FLAG_FD_NONBLOCK	(1<<1)
+#define I915_PERF_FLAG_SINGLE_CONTEXT	(1<<2)
+#define I915_PERF_FLAG_DISABLED         (1<<3)
+
+#define I915_PERF_SAMPLE_OA_REPORT	(1<<0)
+#define I915_PERF_SAMPLE_CTXID		(1<<1)
+#define I915_PERF_SAMPLE_TIMESTAMP	(1<<2)
+
+struct drm_i915_perf_open_param {
+	/* Such as I915_PERF_OA_EVENT */
+	__u32 type;
+
+	/* CLOEXEC, NONBLOCK, SINGLE_CONTEXT, PERIODIC... */
+	__u32 flags;
+
+	/* What to include in samples */
+	__u64 sample_flags;
+
+	/* A specific context to profile */
+	__u32 ctx_id;
+
+	/* Event specific attributes */
+	__u64 __user attr;
+
+	/* OUT */
+	__u32 fd;
+};
+
+#define I915_PERF_IOCTL_ENABLE	_IO('i', 0x0)
+#define I915_PERF_IOCTL_DISABLE	_IO('i', 0x1)
+
+/* Note: same as struct perf_event_header */
+struct drm_i915_perf_event_header {
+	__u32 type;
+	__u16 misc;
+	__u16 size;
+};
+
+enum drm_i915_perf_record_type {
+
+	/*
+	 * struct {
+	 *     struct drm_i915_perf_event_header header;
+	 *
+	 *     { u32 ctx_id; }	    && I915_PERF_SAMPLE_CTXID
+	 *     { u32 timestamp; }   && I915_PERF_SAMPLE_TIMESTAMP
+	 *     { u32 oa_report[]; } && I915_PERF_SAMPLE_OA_REPORT
+	 *
+	 * };
+	 */
+	DRM_I915_PERF_RECORD_SAMPLE = 1,
+
+	DRM_I915_PERF_RECORD_MAX /* non-ABI */
+};
+
 #endif /* _UAPI_I915_DRM_H_ */
-- 
2.5.2



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