On 17/11/2020 11:30, Chris Wilson wrote:
Since we wake the GT up before executing a request, and go to sleep as
soon as it is retired, the GT wake time not only represents how long the
device is powered up, but also provides a summary, albeit an overestimate,
of the device runtime.
Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk>
---
drivers/gpu/drm/i915/gt/intel_gt_pm.c | 45 ++++++++++++++++++++++++
drivers/gpu/drm/i915/gt/intel_gt_pm.h | 2 ++
drivers/gpu/drm/i915/gt/intel_gt_types.h | 24 +++++++++++++
drivers/gpu/drm/i915/i915_debugfs.c | 2 ++
drivers/gpu/drm/i915/i915_pmu.c | 6 ++++
include/uapi/drm/i915_drm.h | 3 +-
6 files changed, 81 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.c
b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
index 274aa0dd7050..dd2f88bed65a 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_pm.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
@@ -39,6 +39,24 @@ static void user_forcewake(struct intel_gt *gt, bool suspend)
intel_gt_pm_put(gt);
}
+static void runtime_begin(struct intel_gt *gt)
+{
+ write_seqcount_begin(>->stats.lock);
+ gt->stats.start = ktime_get();
+ gt->stats.active = true;
+ write_seqcount_end(>->stats.lock);
+}
+
+static void runtime_end(struct intel_gt *gt)
+{
+ write_seqcount_begin(>->stats.lock);
+ gt->stats.active = false;
+ gt->stats.total =
+ ktime_add(gt->stats.total,
+ ktime_sub(ktime_get(), gt->stats.start));
+ write_seqcount_end(>->stats.lock);
+}
+
static int __gt_unpark(struct intel_wakeref *wf)
{
struct intel_gt *gt = container_of(wf, typeof(*gt), wakeref);
@@ -67,6 +85,7 @@ static int __gt_unpark(struct intel_wakeref *wf)
i915_pmu_gt_unparked(i915);
intel_gt_unpark_requests(gt);
+ runtime_begin(gt);
return 0;
}
@@ -79,6 +98,7 @@ static int __gt_park(struct intel_wakeref *wf)
GT_TRACE(gt, "\n");
+ runtime_end(gt);
intel_gt_park_requests(gt);
i915_vma_parked(gt);
@@ -106,6 +126,7 @@ static const struct intel_wakeref_ops wf_ops = {
void intel_gt_pm_init_early(struct intel_gt *gt)
{
intel_wakeref_init(>->wakeref, gt->uncore->rpm, &wf_ops);
+ seqcount_mutex_init(>->stats.lock, >->wakeref.mutex);
}
void intel_gt_pm_init(struct intel_gt *gt)
@@ -339,6 +360,30 @@ int intel_gt_runtime_resume(struct intel_gt *gt)
return intel_uc_runtime_resume(>->uc);
}
+static ktime_t __intel_gt_get_busy_time(const struct intel_gt *gt)
+{
+ ktime_t total = gt->stats.total;
+
+ if (gt->stats.active)
+ total = ktime_add(total,
+ ktime_sub(ktime_get(), gt->stats.start));
+
+ return total;
+}
+
+ktime_t intel_gt_get_busy_time(const struct intel_gt *gt)
+{
+ unsigned int seq;
+ ktime_t total;
+
+ do {
+ seq = read_seqcount_begin(>->stats.lock);
Any specific reasons for read_seqcount_being vs read_seqbegin etc, the
latter being used in engine stats seems to have some kcsan integration
and former a bit more low level.
+ total = __intel_gt_get_busy_time(gt);
+ } while (read_seqcount_retry(>->stats.lock, seq));
+
+ return total;
+}
I wish there was an easy way to extract some sort of struct stats
between engine stats and this and have common helpers, but sadly structs
are not exactly identical.
+
#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
#include "selftest_gt_pm.c"
#endif
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.h
b/drivers/gpu/drm/i915/gt/intel_gt_pm.h
index 60f0e2fbe55c..aa8f2cda946b 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_pm.h
+++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.h
@@ -58,6 +58,8 @@ int intel_gt_resume(struct intel_gt *gt);
void intel_gt_runtime_suspend(struct intel_gt *gt);
int intel_gt_runtime_resume(struct intel_gt *gt);
+ktime_t intel_gt_get_busy_time(const struct intel_gt *gt);
+
static inline bool is_mock_gt(const struct intel_gt *gt)
{
return I915_SELFTEST_ONLY(gt->awake == -ENODEV);
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_types.h
b/drivers/gpu/drm/i915/gt/intel_gt_types.h
index 6d39a4a11bf3..c7bde529feab 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_gt_types.h
@@ -87,6 +87,30 @@ struct intel_gt {
u32 pm_guc_events;
+ struct {
+ bool active;
+
+ /**
+ * @lock: Lock protecting the below fields.
+ */
+ seqcount_mutex_t lock;
+
+ /**
+ * @total: Total time this engine was busy.
+ *
+ * Accumulated time not counting the most recent block in cases
+ * where engine is currently busy (active > 0).
+ */
+ ktime_t total;
+
+ /**
+ * @start: Timestamp of the last idle to active transition.
+ *
+ * Idle is defined as active == 0, active is active > 0.
+ */
+ ktime_t start;
+ } stats;
+
struct intel_engine_cs *engine[I915_NUM_ENGINES];
struct intel_engine_cs *engine_class[MAX_ENGINE_CLASS + 1]
[MAX_ENGINE_INSTANCE + 1];
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c
b/drivers/gpu/drm/i915/i915_debugfs.c
index 77e76b665098..337293c7bb7d 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -1316,6 +1316,8 @@ static int i915_engine_info(struct seq_file *m, void
*unused)
seq_printf(m, "GT awake? %s [%d]\n",
yesno(dev_priv->gt.awake),
atomic_read(&dev_priv->gt.wakeref.count));
+ seq_printf(m, "GT busy: %llu ms\n",
+ ktime_to_ms(intel_gt_get_busy_time(&dev_priv->gt)));
Would it be worth putting something in debugfs_gt_pm.c as well?
seq_printf(m, "CS timestamp frequency: %u Hz\n",
RUNTIME_INFO(dev_priv)->cs_timestamp_frequency_hz);
diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c
index cd786ad12be7..36fc60cf5725 100644
--- a/drivers/gpu/drm/i915/i915_pmu.c
+++ b/drivers/gpu/drm/i915/i915_pmu.c
@@ -488,6 +488,8 @@ config_status(struct drm_i915_private *i915, u64 config)
if (!HAS_RC6(i915))
return -ENODEV;
break;
+ case I915_PMU_BUSY_TIME:
+ break;
default:
return -ENOENT;
}
@@ -595,6 +597,9 @@ static u64 __i915_pmu_event_read(struct perf_event *event)
case I915_PMU_RC6_RESIDENCY:
val = get_rc6(&i915->gt);
break;
+ case I915_PMU_BUSY_TIME:
+ val = ktime_to_ns(intel_gt_get_busy_time(&i915->gt));
+ break;
}
}
@@ -898,6 +903,7 @@ create_event_attributes(struct i915_pmu *pmu)
__event(I915_PMU_REQUESTED_FREQUENCY, "requested-frequency",
"M"),
__event(I915_PMU_INTERRUPTS, "interrupts", NULL),
__event(I915_PMU_RC6_RESIDENCY, "rc6-residency", "ns"),
+ __event(I915_PMU_BUSY_TIME, "busy-time", "ns"),
};
static const struct {
enum drm_i915_pmu_engine_sample sample;
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index fa1f3d62f9a6..b66b7c1fd564 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -177,8 +177,9 @@ enum drm_i915_pmu_engine_sample {
#define I915_PMU_REQUESTED_FREQUENCY __I915_PMU_OTHER(1)
#define I915_PMU_INTERRUPTS __I915_PMU_OTHER(2)
#define I915_PMU_RC6_RESIDENCY __I915_PMU_OTHER(3)
+#define I915_PMU_BUSY_TIME __I915_PMU_OTHER(4)
I'd be tempted to call this I915_PMU_GT_BUSY_TIME - or even better awake
time?
-#define I915_PMU_LAST I915_PMU_RC6_RESIDENCY
+#define I915_PMU_LAST I915_PMU_BUSY_TIME
/* Each region is a minimum of 16k, and there are at most 255 of them.
*/
Code looks fine, but should we be adding a pmu counter?
Regards,
Tvrtko
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