[PATCH] drm/i915/pmu: Use GT parked for estimating RC6 while asleep

* [PATCH] drm/i915/pmu: Use GT parked for estimating RC6 while asleep
@ 2019-08-03 13:29 Chris Wilson
  2019-08-03 14:00 ` ✓ Fi.CI.BAT: success for drm/i915/pmu: Use GT parked for estimating RC6 while asleep (rev2) Patchwork
  2019-08-04 17:39 ` ✓ Fi.CI.IGT: " Patchwork
  0 siblings, 2 replies; 3+ messages in thread
From: Chris Wilson @ 2019-08-03 13:29 UTC (permalink / raw)
  To: intel-gfx

As we track when we put the GT device to sleep upon idling, we can use
that callback to sample the current rc6 counters and record the
timestamp for estimating samples after that point while asleep.

v2: Stick to using ktime_t

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105010
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
 drivers/gpu/drm/i915/i915_debugfs.c |  21 +++--
 drivers/gpu/drm/i915/i915_pmu.c     | 120 ++++++++++++++--------------
 drivers/gpu/drm/i915/i915_pmu.h     |   4 +-
 3 files changed, 69 insertions(+), 76 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 19f156a7f501..80da59b5a1b0 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -39,6 +39,7 @@
 #include "display/intel_psr.h"
 
 #include "gem/i915_gem_context.h"
+#include "gt/intel_gt_pm.h"
 #include "gt/intel_reset.h"
 #include "gt/uc/intel_guc_submission.h"
 
@@ -4063,13 +4064,11 @@ static int i915_sseu_status(struct seq_file *m, void *unused)
 static int i915_forcewake_open(struct inode *inode, struct file *file)
 {
 	struct drm_i915_private *i915 = inode->i_private;
+	struct intel_gt *gt = &i915->gt;
 
-	if (INTEL_GEN(i915) < 6)
-		return 0;
-
-	file->private_data =
-		(void *)(uintptr_t)intel_runtime_pm_get(&i915->runtime_pm);
-	intel_uncore_forcewake_user_get(&i915->uncore);
+	intel_gt_pm_get(gt);
+	if (INTEL_GEN(i915) >= 6)
+		intel_uncore_forcewake_user_get(gt->uncore);
 
 	return 0;
 }
@@ -4077,13 +4076,11 @@ static int i915_forcewake_open(struct inode *inode, struct file *file)
 static int i915_forcewake_release(struct inode *inode, struct file *file)
 {
 	struct drm_i915_private *i915 = inode->i_private;
+	struct intel_gt *gt = &i915->gt;
 
-	if (INTEL_GEN(i915) < 6)
-		return 0;
-
-	intel_uncore_forcewake_user_put(&i915->uncore);
-	intel_runtime_pm_put(&i915->runtime_pm,
-			     (intel_wakeref_t)(uintptr_t)file->private_data);
+	if (INTEL_GEN(i915) >= 6)
+		intel_uncore_forcewake_user_put(&i915->uncore);
+	intel_gt_pm_put(gt);
 
 	return 0;
 }
diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c
index c2e5f6d5c1e0..61d4fa99e413 100644
--- a/drivers/gpu/drm/i915/i915_pmu.c
+++ b/drivers/gpu/drm/i915/i915_pmu.c
@@ -115,19 +115,51 @@ static bool pmu_needs_timer(struct i915_pmu *pmu, bool gpu_active)
 	return enable;
 }
 
+static u64 __get_rc6(struct intel_gt *gt)
+{
+	struct drm_i915_private *i915 = gt->i915;
+	u64 val;
+
+	val = intel_rc6_residency_ns(i915,
+				     IS_VALLEYVIEW(i915) ?
+				     VLV_GT_RENDER_RC6 :
+				     GEN6_GT_GFX_RC6);
+
+	if (HAS_RC6p(i915))
+		val += intel_rc6_residency_ns(i915, GEN6_GT_GFX_RC6p);
+
+	if (HAS_RC6pp(i915))
+		val += intel_rc6_residency_ns(i915, GEN6_GT_GFX_RC6pp);
+
+	return val;
+}
+
 void i915_pmu_gt_parked(struct drm_i915_private *i915)
 {
 	struct i915_pmu *pmu = &i915->pmu;
+	u64 val;
 
 	if (!pmu->base.event_init)
 		return;
 
 	spin_lock_irq(&pmu->lock);
+
+	val = 0;
+	if (pmu->sample[__I915_SAMPLE_RC6].cur)
+		val = __get_rc6(&i915->gt);
+
+	if (val >= pmu->sample[__I915_SAMPLE_RC6_ESTIMATED].cur) {
+		pmu->sample[__I915_SAMPLE_RC6_ESTIMATED].cur = 0;
+		pmu->sample[__I915_SAMPLE_RC6].cur = val;
+	}
+	pmu->sleep_last = ktime_get();
+
 	/*
 	 * Signal sampling timer to stop if only engine events are enabled and
 	 * GPU went idle.
 	 */
 	pmu->timer_enabled = pmu_needs_timer(pmu, false);
+
 	spin_unlock_irq(&pmu->lock);
 }
 
@@ -142,6 +174,11 @@ static void __i915_pmu_maybe_start_timer(struct i915_pmu *pmu)
 	}
 }
 
+static inline s64 ktime_since(const ktime_t kt)
+{
+	return ktime_to_ns(ktime_sub(ktime_get(), kt));
+}
+
 void i915_pmu_gt_unparked(struct drm_i915_private *i915)
 {
 	struct i915_pmu *pmu = &i915->pmu;
@@ -150,10 +187,22 @@ void i915_pmu_gt_unparked(struct drm_i915_private *i915)
 		return;
 
 	spin_lock_irq(&pmu->lock);
+
 	/*
 	 * Re-enable sampling timer when GPU goes active.
 	 */
 	__i915_pmu_maybe_start_timer(pmu);
+
+	/* Estimate how long we slept and accumulate that into rc6 counters */
+	if (pmu->sample[__I915_SAMPLE_RC6].cur) {
+		u64 val;
+
+		val = ktime_since(pmu->sleep_last);
+		val += pmu->sample[__I915_SAMPLE_RC6].cur;
+
+		pmu->sample[__I915_SAMPLE_RC6_ESTIMATED].cur = val;
+	}
+
 	spin_unlock_irq(&pmu->lock);
 }
 
@@ -425,39 +474,18 @@ static int i915_pmu_event_init(struct perf_event *event)
 	return 0;
 }
 
-static u64 __get_rc6(struct intel_gt *gt)
-{
-	struct drm_i915_private *i915 = gt->i915;
-	u64 val;
-
-	val = intel_rc6_residency_ns(i915,
-				     IS_VALLEYVIEW(i915) ?
-				     VLV_GT_RENDER_RC6 :
-				     GEN6_GT_GFX_RC6);
-
-	if (HAS_RC6p(i915))
-		val += intel_rc6_residency_ns(i915, GEN6_GT_GFX_RC6p);
-
-	if (HAS_RC6pp(i915))
-		val += intel_rc6_residency_ns(i915, GEN6_GT_GFX_RC6pp);
-
-	return val;
-}
-
 static u64 get_rc6(struct intel_gt *gt)
 {
-#if IS_ENABLED(CONFIG_PM)
 	struct drm_i915_private *i915 = gt->i915;
-	struct intel_runtime_pm *rpm = &i915->runtime_pm;
 	struct i915_pmu *pmu = &i915->pmu;
-	intel_wakeref_t wakeref;
 	unsigned long flags;
 	u64 val;
 
-	wakeref = intel_runtime_pm_get_if_in_use(rpm);
-	if (wakeref) {
+	spin_lock_irqsave(&pmu->lock, flags);
+
+	if (intel_gt_pm_get_if_awake(gt)) {
 		val = __get_rc6(gt);
-		intel_runtime_pm_put(rpm, wakeref);
+		intel_gt_pm_put(gt);
 
 		/*
 		 * If we are coming back from being runtime suspended we must
@@ -465,19 +493,13 @@ static u64 get_rc6(struct intel_gt *gt)
 		 * previously.
 		 */
 
-		spin_lock_irqsave(&pmu->lock, flags);
-
 		if (val >= pmu->sample[__I915_SAMPLE_RC6_ESTIMATED].cur) {
 			pmu->sample[__I915_SAMPLE_RC6_ESTIMATED].cur = 0;
 			pmu->sample[__I915_SAMPLE_RC6].cur = val;
 		} else {
 			val = pmu->sample[__I915_SAMPLE_RC6_ESTIMATED].cur;
 		}
-
-		spin_unlock_irqrestore(&pmu->lock, flags);
 	} else {
-		struct device *kdev = rpm->kdev;
-
 		/*
 		 * We are runtime suspended.
 		 *
@@ -485,42 +507,16 @@ static u64 get_rc6(struct intel_gt *gt)
 		 * on top of the last known real value, as the approximated RC6
 		 * counter value.
 		 */
-		spin_lock_irqsave(&pmu->lock, flags);
 
-		/*
-		 * After the above branch intel_runtime_pm_get_if_in_use failed
-		 * to get the runtime PM reference we cannot assume we are in
-		 * runtime suspend since we can either: a) race with coming out
-		 * of it before we took the power.lock, or b) there are other
-		 * states than suspended which can bring us here.
-		 *
-		 * We need to double-check that we are indeed currently runtime
-		 * suspended and if not we cannot do better than report the last
-		 * known RC6 value.
-		 */
-		if (pm_runtime_status_suspended(kdev)) {
-			val = pm_runtime_suspended_time(kdev);
+		val = ktime_since(pmu->sleep_last);
+		val += pmu->sample[__I915_SAMPLE_RC6].cur;
 
-			if (!pmu->sample[__I915_SAMPLE_RC6_ESTIMATED].cur)
-				pmu->suspended_time_last = val;
-
-			val -= pmu->suspended_time_last;
-			val += pmu->sample[__I915_SAMPLE_RC6].cur;
-
-			pmu->sample[__I915_SAMPLE_RC6_ESTIMATED].cur = val;
-		} else if (pmu->sample[__I915_SAMPLE_RC6_ESTIMATED].cur) {
-			val = pmu->sample[__I915_SAMPLE_RC6_ESTIMATED].cur;
-		} else {
-			val = pmu->sample[__I915_SAMPLE_RC6].cur;
-		}
-
-		spin_unlock_irqrestore(&pmu->lock, flags);
+		pmu->sample[__I915_SAMPLE_RC6_ESTIMATED].cur = val;
 	}
 
+	spin_unlock_irqrestore(&pmu->lock, flags);
+
 	return val;
-#else
-	return __get_rc6(gt);
-#endif
 }
 
 static u64 __i915_pmu_event_read(struct perf_event *event)
diff --git a/drivers/gpu/drm/i915/i915_pmu.h b/drivers/gpu/drm/i915/i915_pmu.h
index 4fc4f2478301..067dbbf3bdff 100644
--- a/drivers/gpu/drm/i915/i915_pmu.h
+++ b/drivers/gpu/drm/i915/i915_pmu.h
@@ -97,9 +97,9 @@ struct i915_pmu {
 	 */
 	struct i915_pmu_sample sample[__I915_NUM_PMU_SAMPLERS];
 	/**
-	 * @suspended_time_last: Cached suspend time from PM core.
+	 * @sleep_last: Last time GT parked for RC6 estimation.
 	 */
-	u64 suspended_time_last;
+	ktime_t sleep_last;
 	/**
 	 * @i915_attr: Memory block holding device attributes.
 	 */
-- 
2.23.0.rc1

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