The rc6 residency starts ticking from 0 from BIOS POST, but the kernel
starts measuring the time from its boot. If we start measuruing
I915_PMU_RC6_RESIDENCY while the GT is idle, we start our sampling from
0 and then upon first activity (park/unpark) add in all the rc6
residency since boot. After the first park with the sampler engaged, the
sleep/active counters are aligned.
v2: With a wakeref to be sure
Fixes: df6a42053513 ("drm/i915/pmu: Ensure monotonic rc6")
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_pmu.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c
index 28a82c849bac..ec0299490dd4 100644
--- a/drivers/gpu/drm/i915/i915_pmu.c
+++ b/drivers/gpu/drm/i915/i915_pmu.c
@@ -637,8 +637,10 @@ static void i915_pmu_enable(struct perf_event *event)
container_of(event->pmu, typeof(*i915), pmu.base);
unsigned int bit = event_enabled_bit(event);
struct i915_pmu *pmu = &i915->pmu;
+ intel_wakeref_t wakeref;
unsigned long flags;
+ wakeref = intel_runtime_pm_get(&i915->runtime_pm);
spin_lock_irqsave(&pmu->lock, flags);
/*
@@ -648,6 +650,14 @@ static void i915_pmu_enable(struct perf_event *event)
BUILD_BUG_ON(ARRAY_SIZE(pmu->enable_count) != I915_PMU_MASK_BITS);
GEM_BUG_ON(bit >= ARRAY_SIZE(pmu->enable_count));
GEM_BUG_ON(pmu->enable_count[bit] == ~0);
+
+ if (pmu->enable_count[bit] == 0 &&
+ config_enabled_mask(I915_PMU_RC6_RESIDENCY) & BIT_ULL(bit)) {
+ pmu->sample[__I915_SAMPLE_RC6_LAST_REPORTED].cur = 0;
+ pmu->sample[__I915_SAMPLE_RC6].cur = __get_rc6(&i915->gt);
+ pmu->sleep_last = ktime_get();
+ }
+
pmu->enable |= BIT_ULL(bit);
pmu->enable_count[bit]++;
@@ -688,6 +698,8 @@ static void i915_pmu_enable(struct perf_event *event)
* an existing non-zero value.
*/
local64_set(&event->hw.prev_count, __i915_pmu_event_read(event));
+
+ intel_runtime_pm_put(&i915->runtime_pm, wakeref);
}
static void i915_pmu_disable(struct perf_event *event)
--
2.25.0.rc2
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