From b319cc594e666061b22331da654606b92730343a Mon Sep 17 00:00:00 2001 From: Tvrtko Ursulin Date: Fri, 19 May 2023 08:49:44 -0700 Subject: [PATCH] drm/i915/pmu: Add reference counting to the sampling timer We do not want to have timers per tile and waste CPU cycles and energy via multiple wake-up sources, for a relatively un-important task of PMU sampling, so keeping a single timer works well. But we also do not want the first GT which goes idle to turn off the timer. Add some reference counting, via a mask of unparked GTs, to solve this. v2: Drop the check for unparked in i915_sample (Ashutosh) v3: Revert v2 (Tvrtko) Signed-off-by: Tvrtko Ursulin Reviewed-by: Umesh Nerlige Ramappa Signed-off-by: Umesh Nerlige Ramappa Reviewed-by: Ashutosh Dixit Link: https://patchwork.freedesktop.org/patch/msgid/20230519154946.3751971-6-umesh.nerlige.ramappa@intel.com --- drivers/gpu/drm/i915/i915_pmu.c | 12 ++++++++++-- drivers/gpu/drm/i915/i915_pmu.h | 4 ++++ 2 files changed, 14 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c index 890693f..ecb57a9 100644 --- a/drivers/gpu/drm/i915/i915_pmu.c +++ b/drivers/gpu/drm/i915/i915_pmu.c @@ -262,7 +262,9 @@ void i915_pmu_gt_parked(struct intel_gt *gt) * Signal sampling timer to stop if only engine events are enabled and * GPU went idle. */ - pmu->timer_enabled = pmu_needs_timer(pmu, false); + pmu->unparked &= ~BIT(gt->info.id); + if (pmu->unparked == 0) + pmu->timer_enabled = pmu_needs_timer(pmu, false); spin_unlock_irq(&pmu->lock); } @@ -279,7 +281,10 @@ void i915_pmu_gt_unparked(struct intel_gt *gt) /* * Re-enable sampling timer when GPU goes active. */ - __i915_pmu_maybe_start_timer(pmu); + if (pmu->unparked == 0) + __i915_pmu_maybe_start_timer(pmu); + + pmu->unparked |= BIT(gt->info.id); spin_unlock_irq(&pmu->lock); } @@ -449,6 +454,9 @@ static enum hrtimer_restart i915_sample(struct hrtimer *hrtimer) */ for_each_gt(gt, i915, i) { + if (!(pmu->unparked & BIT(i))) + continue; + engines_sample(gt, period_ns); if (i == 0) /* FIXME */ diff --git a/drivers/gpu/drm/i915/i915_pmu.h b/drivers/gpu/drm/i915/i915_pmu.h index a686fd7..3a81126 100644 --- a/drivers/gpu/drm/i915/i915_pmu.h +++ b/drivers/gpu/drm/i915/i915_pmu.h @@ -77,6 +77,10 @@ struct i915_pmu { */ spinlock_t lock; /** + * @unparked: GT unparked mask. + */ + unsigned int unparked; + /** * @timer: Timer for internal i915 PMU sampling. */ struct hrtimer timer; -- 2.7.4