[PATCH 1/8] drm/i915/gt: Show the per-engine runtime in sysfs

[Chris Wilson]

Since we already report the per-engine runtime via PMU (using sampling
if a direct measure is not available), and in debugfs, also trivially
include the information for each engine under sysfs as a read-only
property. We only present the total milliseconds to hide any misleading
accuracy and to purposely reduce the precision of the global
unprivileged information.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210123153733.18139-1-chris@chris-wilson.co.uk
---
 drivers/gpu/drm/i915/gt/sysfs_engines.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/gpu/drm/i915/gt/sysfs_engines.c b/drivers/gpu/drm/i915/gt/sysfs_engines.c
index 967031056202..57ef5383dd4e 100644
--- a/drivers/gpu/drm/i915/gt/sysfs_engines.c
+++ b/drivers/gpu/drm/i915/gt/sysfs_engines.c
@@ -411,6 +411,19 @@ heartbeat_default(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 static struct kobj_attribute heartbeat_interval_def =
 __ATTR(heartbeat_interval_ms, 0444, heartbeat_default, NULL);
 
+static ssize_t
+runtime_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	struct intel_engine_cs *engine = kobj_to_engine(kobj);
+	ktime_t dummy;
+
+	return sprintf(buf, "%llu\n",
+		       ktime_to_ms(intel_engine_get_busy_time(engine, &dummy)));
+}
+
+static struct kobj_attribute runtime_attr =
+__ATTR(runtime_ms, 0444, runtime_show, NULL);
+
 static void kobj_engine_release(struct kobject *kobj)
 {
 	kfree(kobj);
@@ -521,6 +534,10 @@ void intel_engines_add_sysfs(struct drm_i915_private *i915)
 		    sysfs_create_file(kobj, &preempt_timeout_attr.attr))
 			goto err_engine;
 
+		if (intel_engine_supports_stats(engine) &&
+		    sysfs_create_file(kobj, &runtime_attr.attr))
+			goto err_engine;
+
 		add_defaults(container_of(kobj, struct kobj_engine, base));
 
 		if (0) {
-- 
2.20.1