From d0aa694b923960351ab79df021de7bbd7728d5cc Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Sat, 23 Feb 2019 00:01:02 +0000 Subject: [PATCH] drm/i915/pmu: Always sample an active ringbuffer As we no longer have a precise indication of requests queued to an engine, make no presumptions and just sample the ring registers to see if the engine is busy. v2: Report busy while the ring is idling on a semaphore/event. v3: Give the struct a name! v4: Always 0 outside the powerwell; trusting the powerwell is accurate enough for our sampling pmu. v5: Protect against gen7 mmio madness and try to improve grammar Signed-off-by: Chris Wilson Cc: Tvrtko Ursulin Cc: Mika Kuoppala Reviewed-by: Mika Kuoppala Link: https://patchwork.freedesktop.org/patch/msgid/20190223000102.14290-1-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/i915_pmu.c | 65 +++++++++++-------------- drivers/gpu/drm/i915/intel_ringbuffer.h | 2 +- 2 files changed, 29 insertions(+), 38 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c index 13d70b90dd0f..6560c356f279 100644 --- a/drivers/gpu/drm/i915/i915_pmu.c +++ b/drivers/gpu/drm/i915/i915_pmu.c @@ -148,14 +148,6 @@ void i915_pmu_gt_unparked(struct drm_i915_private *i915) spin_unlock_irq(&i915->pmu.lock); } -static bool grab_forcewake(struct drm_i915_private *i915, bool fw) -{ - if (!fw) - intel_uncore_forcewake_get(i915, FORCEWAKE_ALL); - - return true; -} - static void add_sample(struct i915_pmu_sample *sample, u32 val) { @@ -168,49 +160,48 @@ engines_sample(struct drm_i915_private *dev_priv, unsigned int period_ns) struct intel_engine_cs *engine; enum intel_engine_id id; intel_wakeref_t wakeref; - bool fw = false; + unsigned long flags; if ((dev_priv->pmu.enable & ENGINE_SAMPLE_MASK) == 0) return; - if (!dev_priv->gt.awake) - return; - - wakeref = intel_runtime_pm_get_if_in_use(dev_priv); + wakeref = 0; + if (READ_ONCE(dev_priv->gt.awake)) + wakeref = intel_runtime_pm_get_if_in_use(dev_priv); if (!wakeref) return; + spin_lock_irqsave(&dev_priv->uncore.lock, flags); for_each_engine(engine, dev_priv, id) { - u32 current_seqno = intel_engine_get_seqno(engine); - u32 last_seqno = intel_engine_last_submit(engine); + struct intel_engine_pmu *pmu = &engine->pmu; + bool busy; u32 val; - val = !i915_seqno_passed(current_seqno, last_seqno); - - 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)))) { - fw = grab_forcewake(dev_priv, fw); - - val = I915_READ_FW(RING_CTL(engine->mmio_base)); - } else { - val = 0; - } + val = I915_READ_FW(RING_CTL(engine->mmio_base)); + if (val == 0) /* powerwell off => engine idle */ + continue; if (val & RING_WAIT) - add_sample(&engine->pmu.sample[I915_SAMPLE_WAIT], - period_ns); - + add_sample(&pmu->sample[I915_SAMPLE_WAIT], period_ns); if (val & RING_WAIT_SEMAPHORE) - add_sample(&engine->pmu.sample[I915_SAMPLE_SEMA], - period_ns); - } + add_sample(&pmu->sample[I915_SAMPLE_SEMA], period_ns); - if (fw) - intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL); + /* + * While waiting on a semaphore or event, MI_MODE reports the + * ring as idle. However, previously using the seqno, and with + * execlists sampling, we account for the ring waiting as the + * engine being busy. Therefore, we record the sample as being + * busy if either waiting or !idle. + */ + busy = val & (RING_WAIT_SEMAPHORE | RING_WAIT); + if (!busy) { + val = I915_READ_FW(RING_MI_MODE(engine->mmio_base)); + busy = !(val & MODE_IDLE); + } + if (busy) + add_sample(&pmu->sample[I915_SAMPLE_BUSY], period_ns); + } + spin_unlock_irqrestore(&dev_priv->uncore.lock, flags); intel_runtime_pm_put(dev_priv, wakeref); } diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h index 710ffb221775..5d45ad4ecca9 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.h +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h @@ -392,7 +392,7 @@ struct intel_engine_cs { bool irq_armed; } breadcrumbs; - struct { + struct intel_engine_pmu { /** * @enable: Bitmask of enable sample events on this engine. * -- 2.30.2