[PATCH] pmu measure period

[Tvrtko Ursulin]

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

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
 drivers/gpu/drm/i915/i915_pmu.c | 61 ++++++++++++++++++++++-----------
 drivers/gpu/drm/i915/i915_pmu.h |  8 +++++
 2 files changed, 49 insertions(+), 20 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c
index dc87797db500..ff3e3f865567 100644
--- a/drivers/gpu/drm/i915/i915_pmu.c
+++ b/drivers/gpu/drm/i915/i915_pmu.c
@@ -127,6 +127,7 @@ static void __i915_pmu_maybe_start_timer(struct drm_i915_private *i915)
 {
 	if (!i915->pmu.timer_enabled && pmu_needs_timer(i915, true)) {
 		i915->pmu.timer_enabled = true;
+		i915->pmu.timer_last = ktime_get();
 		hrtimer_start_range_ns(&i915->pmu.timer,
 				       ns_to_ktime(PERIOD), 0,
 				       HRTIMER_MODE_REL_PINNED);
@@ -155,12 +156,13 @@ static bool grab_forcewake(struct drm_i915_private *i915, bool fw)
 }
 
 static void
-update_sample(struct i915_pmu_sample *sample, u32 unit, u32 val)
+add_sample(struct i915_pmu_sample *sample, u32 val)
 {
-	sample->cur += mul_u32_u32(val, unit);
+	sample->cur += val;
 }
 
-static void engines_sample(struct drm_i915_private *dev_priv)
+static void
+engines_sample(struct drm_i915_private *dev_priv, unsigned int period_ns)
 {
 	struct intel_engine_cs *engine;
 	enum intel_engine_id id;
@@ -182,8 +184,9 @@ static void engines_sample(struct drm_i915_private *dev_priv)
 
 		val = !i915_seqno_passed(current_seqno, last_seqno);
 
-		update_sample(&engine->pmu.sample[I915_SAMPLE_BUSY],
-			      PERIOD, val);
+		if (val)
+			add_sample(&engine->pmu.sample[I915_SAMPLE_BUSY],
+				   period_ns);
 
 		if (val && (engine->pmu.enable &
 		    (BIT(I915_SAMPLE_WAIT) | BIT(I915_SAMPLE_SEMA)))) {
@@ -194,11 +197,13 @@ static void engines_sample(struct drm_i915_private *dev_priv)
 			val = 0;
 		}
 
-		update_sample(&engine->pmu.sample[I915_SAMPLE_WAIT],
-			      PERIOD, !!(val & RING_WAIT));
+		if (val & RING_WAIT)
+			add_sample(&engine->pmu.sample[I915_SAMPLE_WAIT],
+				   period_ns);
 
-		update_sample(&engine->pmu.sample[I915_SAMPLE_SEMA],
-			      PERIOD, !!(val & RING_WAIT_SEMAPHORE));
+		if (val & RING_WAIT_SEMAPHORE)
+			add_sample(&engine->pmu.sample[I915_SAMPLE_SEMA],
+				   period_ns);
 	}
 
 	if (fw)
@@ -207,7 +212,14 @@ static void engines_sample(struct drm_i915_private *dev_priv)
 	intel_runtime_pm_put(dev_priv);
 }
 
-static void frequency_sample(struct drm_i915_private *dev_priv)
+static void
+add_sample_mult(struct i915_pmu_sample *sample, u32 val, u32 mul)
+{
+	sample->cur += mul_u32_u32(val, mul);
+}
+
+static void
+frequency_sample(struct drm_i915_private *dev_priv, unsigned int period_ns)
 {
 	if (dev_priv->pmu.enable &
 	    config_enabled_mask(I915_PMU_ACTUAL_FREQUENCY)) {
@@ -221,15 +233,17 @@ static void frequency_sample(struct drm_i915_private *dev_priv)
 			intel_runtime_pm_put(dev_priv);
 		}
 
-		update_sample(&dev_priv->pmu.sample[__I915_SAMPLE_FREQ_ACT],
-			      1, intel_gpu_freq(dev_priv, val));
+		add_sample_mult(&dev_priv->pmu.sample[__I915_SAMPLE_FREQ_ACT],
+			        intel_gpu_freq(dev_priv, val),
+				period_ns / 1000);
 	}
 
 	if (dev_priv->pmu.enable &
 	    config_enabled_mask(I915_PMU_REQUESTED_FREQUENCY)) {
-		update_sample(&dev_priv->pmu.sample[__I915_SAMPLE_FREQ_REQ], 1,
-			      intel_gpu_freq(dev_priv,
-					     dev_priv->gt_pm.rps.cur_freq));
+		add_sample_mult(&dev_priv->pmu.sample[__I915_SAMPLE_FREQ_REQ],
+				intel_gpu_freq(dev_priv,
+					       dev_priv->gt_pm.rps.cur_freq),
+				period_ns / 1000);
 	}
 }
 
@@ -237,14 +251,21 @@ static enum hrtimer_restart i915_sample(struct hrtimer *hrtimer)
 {
 	struct drm_i915_private *i915 =
 		container_of(hrtimer, struct drm_i915_private, pmu.timer);
+	unsigned int period_ns;
+	ktime_t now;
 
 	if (!READ_ONCE(i915->pmu.timer_enabled))
 		return HRTIMER_NORESTART;
 
-	engines_sample(i915);
-	frequency_sample(i915);
+	now = ktime_get();
+	period_ns = ktime_to_ns(ktime_sub(now, i915->pmu.timer_last));
+	i915->pmu.timer_last = now;
+
+	engines_sample(i915, period_ns);
+	frequency_sample(i915, period_ns);
+
+	hrtimer_forward(hrtimer, now, ns_to_ktime(PERIOD));
 
-	hrtimer_forward_now(hrtimer, ns_to_ktime(PERIOD));
 	return HRTIMER_RESTART;
 }
 
@@ -519,12 +540,12 @@ static u64 __i915_pmu_event_read(struct perf_event *event)
 		case I915_PMU_ACTUAL_FREQUENCY:
 			val =
 			   div_u64(i915->pmu.sample[__I915_SAMPLE_FREQ_ACT].cur,
-				   FREQUENCY);
+				   1000000 /* to MHz */);
 			break;
 		case I915_PMU_REQUESTED_FREQUENCY:
 			val =
 			   div_u64(i915->pmu.sample[__I915_SAMPLE_FREQ_REQ].cur,
-				   FREQUENCY);
+				   1000000 /* to MHz */);
 			break;
 		case I915_PMU_INTERRUPTS:
 			val = count_interrupts(i915);
diff --git a/drivers/gpu/drm/i915/i915_pmu.h b/drivers/gpu/drm/i915/i915_pmu.h
index 2ba735299f7c..7f164ca3db12 100644
--- a/drivers/gpu/drm/i915/i915_pmu.h
+++ b/drivers/gpu/drm/i915/i915_pmu.h
@@ -65,6 +65,14 @@ struct i915_pmu {
 	 * event types.
 	 */
 	u64 enable;
+
+	/**
+	 * @timer_last:
+	 *
+	 * Timestmap of the previous timer invocation.
+	 */
+	ktime_t timer_last;
+
 	/**
 	 * @enable_count: Reference counts for the enabled events.
 	 *
-- 
2.17.0