[Intel-gfx] [RFC 6/8] drm/i915: Expose per-engine client busyness

Tvrtko Ursulin
2020-01-10T13:31:05Z

From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

Expose per-client and per-engine busyness under the previously added sysfs
client root.

The new files are one per-engine instance and located under the 'busy'
directory. Each contains a monotonically increasing nano-second resolution
times each client's jobs were executing on the GPU.

This enables userspace to create a top-like tool for GPU utilization:

==========================================================================
intel-gpu-top - 935/ 935 MHz; 0% RC6; 14.73 Watts; 1097 irqs/s

IMC reads: 1401 MiB/s
IMC writes: 4 MiB/s

ENGINE BUSY MI_SEMA MI_WAIT
Render/3D/0 63.73% |███████████████████ | 3% 0%
Blitter/0 9.53% |██▊ | 6% 0%
Video/0 39.32% |███████████▊ | 16% 0%
Video/1 15.62% |████▋ | 0% 0%
VideoEnhance/0 0.00% | | 0% 0%

PID NAME RCS BCS VCS VECS
4084 gem_wsim |█████▌ ||█ || || |
4086 gem_wsim |█▌ || ||███ || |
==========================================================================

v2: Use intel_context_engine_get_busy_time.
v3: New directory structure.
v4: Rebase.
v5: sysfs_attr_init.
v6: Small tidy in i915_gem_add_client.
v7: Rebase to be engine class based.
v8:
* Always enable stats.
* Walk all client contexts.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
drivers/gpu/drm/i915/i915_drm_client.c | 127 ++++++++++++++++++++++++-
drivers/gpu/drm/i915/i915_drm_client.h | 13 +++
2 files changed, 139 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_drm_client.c b/drivers/gpu/drm/i915/i915_drm_client.c
index 195777b95891..55b2f86cc4c1 100644
--- a/drivers/gpu/drm/i915/i915_drm_client.c
+++ b/drivers/gpu/drm/i915/i915_drm_client.c
@@ -8,7 +8,11 @@
#include <linux/slab.h>
#include <linux/types.h>

+#include <uapi/drm/i915_drm.h>
+
#include "i915_drm_client.h"
+#include "gem/i915_gem_context.h"
+#include "i915_drv.h"
#include "i915_gem.h"
#include "i915_utils.h"

@@ -36,13 +40,62 @@ show_client_pid(struct device *kdev, struct device_attribute *attr, char *buf)
client->closed ? ">" : "");
}

+static u64
+sw_busy_add(struct i915_gem_context *ctx, unsigned int engine_class)
+{
+ struct i915_gem_engines *engines = rcu_dereference(ctx->engines);
+ struct i915_gem_engines_iter it;
+ struct intel_context *ce;
+ u64 total = 0;
+
+ for_each_gem_engine(ce, engines, it) {
+ if (ce->engine->uabi_class != engine_class)
+ continue;
+
+ total += ktime_to_ns(intel_context_get_busy_time(ce));
+ }
+
+ return total;
+}
+
+static ssize_t
+show_client_busy(struct device *kdev, struct device_attribute *attr, char *buf)
+{
+ struct i915_engine_busy_attribute *i915_attr =
+ container_of(attr, typeof(*i915_attr), attr);
+ struct list_head *list = &i915_attr->client->ctx_list;
+ unsigned int engine_class = i915_attr->engine_class;
+ struct i915_gem_context *ctx;
+ u64 total = 0;
+
+ if (i915_attr->no_busy_stats)
+ return -ENODEV;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(ctx, list, client_link)
+ total += sw_busy_add(ctx, engine_class);
+ rcu_read_unlock();
+
+ return snprintf(buf, PAGE_SIZE, "%llu\n", total);
+}
+
+static const char *uabi_class_names[] = {
+ [I915_ENGINE_CLASS_RENDER] = "0",
+ [I915_ENGINE_CLASS_COPY] = "1",
+ [I915_ENGINE_CLASS_VIDEO] = "2",
+ [I915_ENGINE_CLASS_VIDEO_ENHANCE] = "3",
+};
+
int
__i915_drm_client_register(struct i915_drm_client *client,
struct task_struct *task)
{
struct i915_drm_clients *clients = client->clients;
+ struct drm_i915_private *i915 =
+ container_of(clients, typeof(*i915), clients);
+ struct intel_engine_cs *engine;
struct device_attribute *attr;
- int ret = -ENOMEM;
+ int i, ret = -ENOMEM;
char idstr[32];

if (!clients->root)
@@ -77,10 +130,71 @@ __i915_drm_client_register(struct i915_drm_client *client,
if (ret)
goto err_attr;

+ if (HAS_LOGICAL_RING_CONTEXTS(i915)) {
+ client->busy_root =
+ kobject_create_and_add("busy", client->root);
+ if (!client->busy_root)
+ goto err_attr;
+
+ for (i = 0; i < ARRAY_SIZE(uabi_class_names); i++) {
+ struct i915_engine_busy_attribute *i915_attr =
+ &client->attr.busy[i];
+
+ i915_attr->client = client;
+ i915_attr->engine_class = i;
+
+ attr = &i915_attr->attr;
+
+ sysfs_attr_init(&attr->attr);
+
+ attr->attr.name = uabi_class_names[i];
+ attr->attr.mode = 0444;
+ attr->show = show_client_busy;
+
+ ret = sysfs_create_file(client->busy_root,
+ (struct attribute *)attr);
+ if (ret)
+ goto err_busy;
+ }
+
+ /* Enable busy stats on all engines. */
+ i = 0;
+ for_each_uabi_engine(engine, i915) {
+ ret = intel_enable_engine_stats(engine);
+ if (ret) {
+ int j, k;
+
+ /* Unwind if not available. */
+ j = 0;
+ for_each_uabi_engine(engine, i915) {
+ if (j++ == i)
+ break;
+
+ intel_disable_engine_stats(engine);
+ }
+
+ for (k = 0;
+ k < ARRAY_SIZE(uabi_class_names);
+ k++) {
+ GEM_WARN_ON(client->attr.busy[k].no_busy_stats);
+ client->attr.busy[k].no_busy_stats = true;
+ }
+
+ dev_notice_once(i915->drm.dev,
+ "Engine busy stats not available! (%d)",
+ ret);
+ break;
+ }
+ i++;
+ }
+ }
+
client->pid = get_task_pid(task, PIDTYPE_PID);

return 0;

+err_busy:
+ kobject_put(client->busy_root);
err_attr:
kobject_put(client->root);
err_client:
@@ -91,9 +205,20 @@ __i915_drm_client_register(struct i915_drm_client *client,

void __i915_drm_client_unregister(struct i915_drm_client *client)
{
+ struct i915_drm_clients *clients = client->clients;
+ struct drm_i915_private *i915 =
+ container_of(clients, typeof(*i915), clients);
+ struct intel_engine_cs *engine;
+
if (!client->name)
return; /* fbdev client or error during drm open */

+ if (client->busy_root && !client->attr.busy[0].no_busy_stats) {
+ for_each_uabi_engine(engine, i915)
+ intel_disable_engine_stats(engine);
+ }
+
+ kobject_put(fetch_and_zero(&client->busy_root));
kobject_put(fetch_and_zero(&client->root));
put_pid(fetch_and_zero(&client->pid));
kfree(fetch_and_zero(&client->name));
diff --git a/drivers/gpu/drm/i915/i915_drm_client.h b/drivers/gpu/drm/i915/i915_drm_client.h
index 16d8db075a7d..4b4b9ea0abdf 100644
--- a/drivers/gpu/drm/i915/i915_drm_client.h
+++ b/drivers/gpu/drm/i915/i915_drm_client.h
@@ -17,11 +17,22 @@
#include <linux/spinlock.h>
#include <linux/xarray.h>

+#include "gt/intel_engine_types.h"
+
struct i915_drm_clients {
struct xarray xarray;
struct kobject *root;
};

+struct i915_drm_client;
+
+struct i915_engine_busy_attribute {
+ struct device_attribute attr;
+ struct i915_drm_client *client;
+ unsigned int engine_class;
+ bool no_busy_stats;
+};
+
struct i915_drm_client {
struct kref kref;

@@ -38,9 +49,11 @@ struct i915_drm_client {
struct i915_drm_clients *clients;

struct kobject *root;
+ struct kobject *busy_root;
struct {
struct device_attribute pid;
struct device_attribute name;
+ struct i915_engine_busy_attribute busy[MAX_ENGINE_CLASS];
} attr;
};

--
2.20.1