[RFC 17/17] drm/i915: Add sysfs toggle to enable per-client engine stats

Tvrtko Ursulin
2017-10-25T15:36:55Z

By default we are not collecting any per-engine and per-context
statistcs.

Add a new sysfs toggle to enable this facility:

$ echo 1 >/sys/class/drm/card0/clients/enable_stats

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
drivers/gpu/drm/i915/i915_drv.h | 2 ++
drivers/gpu/drm/i915/i915_sysfs.c | 71 +++++++++++++++++++++++++++++++++++++++
2 files changed, 73 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index d74111b397b4..83d37ce3a235 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2769,6 +2769,8 @@ struct drm_i915_private {

struct kobject *clients_root;
atomic_t client_serial;
+ struct device_attribute client_stats_attr;
+ bool client_stats_enabled;

/*
* NOTE: This is the dri1/ums dungeon, don't add stuff here. Your patch
diff --git a/drivers/gpu/drm/i915/i915_sysfs.c b/drivers/gpu/drm/i915/i915_sysfs.c
index 05617e0665bf..f48c9aae26b1 100644
--- a/drivers/gpu/drm/i915/i915_sysfs.c
+++ b/drivers/gpu/drm/i915/i915_sysfs.c
@@ -559,9 +559,66 @@ static void i915_setup_error_capture(struct device *kdev) {}
static void i915_teardown_error_capture(struct device *kdev) {}
#endif

+static ssize_t
+show_client_stats(struct device *kdev, struct device_attribute *attr, char *buf)
+{
+ struct drm_i915_private *i915 =
+ container_of(attr, struct drm_i915_private, client_stats_attr);
+
+ return snprintf(buf, PAGE_SIZE, "%u\n", i915->client_stats_enabled);
+}
+
+static ssize_t
+store_client_stats(struct device *kdev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct drm_i915_private *i915 =
+ container_of(attr, struct drm_i915_private, client_stats_attr);
+ bool disable = false;
+ bool enable = false;
+ bool val = false;
+ struct intel_engine_cs *engine;
+ enum intel_engine_id id;
+ int ret;
+
+ if (!i915_modparams.enable_execlists)
+ return -EINVAL;
+
+ ret = kstrtobool(buf, &val);
+ if (ret)
+ return ret;
+
+ ret = i915_mutex_lock_interruptible(&i915->drm);
+ if (ret)
+ return ret;
+
+ if (val && !i915->client_stats_enabled)
+ enable = true;
+ else if (!val && i915->client_stats_enabled)
+ disable = true;
+
+ if (!enable && !disable)
+ goto out;
+
+ for_each_engine(engine, i915, id) {
+ if (enable)
+ intel_enable_engine_stats(engine);
+ else if (disable)
+ intel_disable_engine_stats(engine);
+ }
+
+ i915->client_stats_enabled = val;
+
+out:
+ mutex_unlock(&i915->drm.struct_mutex);
+
+ return count;
+}
+
void i915_setup_sysfs(struct drm_i915_private *dev_priv)
{
struct device *kdev = dev_priv->drm.primary->kdev;
+ struct device_attribute *attr;
int ret;

dev_priv->clients_root =
@@ -569,6 +626,17 @@ void i915_setup_sysfs(struct drm_i915_private *dev_priv)
if (!dev_priv->clients_root)
DRM_ERROR("Per-client sysfs setup failed\n");

+ attr = &dev_priv->client_stats_attr;
+ attr->attr.name = "enable_stats";
+ attr->attr.mode = 0664;
+ attr->show = show_client_stats;
+ attr->store = store_client_stats;
+
+ ret = sysfs_create_file(dev_priv->clients_root,
+ (struct attribute *)attr);
+ if (ret)
+ DRM_ERROR("Per-client sysfs setup failed! (%d)\n", ret);
+
#ifdef CONFIG_PM
if (HAS_RC6(dev_priv)) {
ret = sysfs_merge_group(&kdev->kobj,
@@ -630,6 +698,9 @@ void i915_teardown_sysfs(struct drm_i915_private *dev_priv)
sysfs_unmerge_group(&kdev->kobj, &rc6p_attr_group);
#endif

+ sysfs_remove_file(dev_priv->clients_root,
+ (struct attribute *)&dev_priv->client_stats_attr);
+
if (dev_priv->clients_root)
kobject_put(dev_priv->clients_root);