On 19/01/2018 13:45, Tvrtko Ursulin wrote:
From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Expose per-client and per-engine busyness under the previously added sysfs
client root.
The new file is named 'busy' and contains a list of, one line for each
engine, monotonically increasing nano-second resolution times each
client's jobs were executing on the GPU.
$ cat /sys/class/drm/card0/clients/5/busy
32516602
0
0
0
This data can serve as an interface to implement a top like utility for
GPU jobs. For instance I have prototyped a tool in IGT which produces
periodic output like:
neverball[ 6011]: rcs0: 41.01% bcs0: 0.00% vcs0: 0.00% vecs0: 0.00%
Xorg[ 5664]: rcs0: 31.16% bcs0: 0.00% vcs0: 0.00% vecs0: 0.00%
xfwm4[ 5727]: rcs0: 0.00% bcs0: 0.00% vcs0: 0.00% vecs0: 0.00%
This tools can also be extended to use the i915 PMU and show overall engine
busyness, and engine loads using the queue depth metric.
v2: Use intel_context_engine_get_busy_time.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_drv.h | 1 +
drivers/gpu/drm/i915/i915_gem.c | 66 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 67 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index a2a883aaa59e..a96cfdfcba03 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -350,6 +350,7 @@ struct drm_i915_file_private {
struct {
struct device_attribute pid;
struct device_attribute name;
+ struct device_attribute busy;
} attr;
};
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 7fdd892aa32a..c8753e4d66c4 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -5538,6 +5538,57 @@ show_client_pid(struct device *kdev, struct device_attribute *attr, char *buf)
return snprintf(buf, PAGE_SIZE, "%u", file_priv->client_pid);
}
+struct busy_ctx {
+ u64 total[I915_NUM_ENGINES];
+};
+
+static int busy_add(int _id, void *p, void *data)
+{
+ struct i915_gem_context *ctx = p;
+ struct busy_ctx *bc = data;
+ struct intel_engine_cs *engine;
+ enum intel_engine_id id;
+
+ for_each_engine(engine, ctx->i915, id)
+ bc->total[id] +=
+ ktime_to_ns(intel_context_engine_get_busy_time(ctx, engine));
+
+ return 0;
+}
+
+static ssize_t
+show_client_busy(struct device *kdev, struct device_attribute *attr, char *buf)
+{
+ struct drm_i915_file_private *file_priv =
+ container_of(attr, struct drm_i915_file_private, attr.busy);
+ struct drm_i915_private *i915 = file_priv->dev_priv;
+ unsigned int len = PAGE_SIZE;
+ struct busy_ctx bc = { };
+ ssize_t res = 0;
+ struct intel_engine_cs *engine;
+ enum intel_engine_id id;
+ ssize_t ret;
+
+ ret = i915_mutex_lock_interruptible(&i915->drm);
+ if (ret)
+ return ret;
+
+ idr_for_each(&file_priv->context_idr, busy_add, &bc);
+
+ mutex_unlock(&i915->drm.struct_mutex);
This is the part which could be done more efficiently by adding an
aggregated busyness to file_priv as a couple atomic_t (busy count and
active count I think), and incrementing it from the
context_in/context_out hooks as they go. Then the client busyness query
would be both lockless and wouldn't need to iterate the
file_priv->context_id.
It would probably be preferable to do it like that instead of having to
take struct_mutex here. But until there is some idea if people are
warming up to this feature in general I did not bother fully polishing it.
Regards,
Tvrtko
+
+ for_each_engine(engine, i915, id) {
+ ret = snprintf(buf, len, "%llu\n", bc.total[id]);
+ if (ret <= 0)
+ break;
+ res += ret;
+ len -= ret;
+ buf += ret;
+ }
+
+ return res;
+}
+
int
i915_gem_add_client(struct drm_i915_private *i915,
struct drm_i915_file_private *file_priv,
@@ -5578,10 +5629,23 @@ i915_gem_add_client(struct drm_i915_private *i915,
if (ret)
goto err_attr_pid;
+ attr = &file_priv->attr.busy;
+ attr->attr.name = "busy";
+ attr->attr.mode = 0444;
+ attr->show = show_client_busy;
+
+ ret = sysfs_create_file(file_priv->client_root,
+ (struct attribute *)attr);
+ if (ret)
+ goto err_attr_busy;
+
file_priv->client_pid = pid_nr(get_task_pid(task, PIDTYPE_PID));
return 0;
+err_attr_busy:
+ sysfs_remove_file(file_priv->client_root,
+ (struct attribute *)&file_priv->attr.pid);
err_attr_pid:
sysfs_remove_file(file_priv->client_root,
(struct attribute *)&file_priv->attr.name);
@@ -5595,6 +5659,8 @@ i915_gem_add_client(struct drm_i915_private *i915,
void i915_gem_remove_client(struct drm_i915_file_private *file_priv)
{
+ sysfs_remove_file(file_priv->client_root,
+ (struct attribute *)&file_priv->attr.busy);
sysfs_remove_file(file_priv->client_root,
(struct attribute *)&file_priv->attr.pid);
sysfs_remove_file(file_priv->client_root,
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