From: Rob Clark robdclark@chromium.org
Signed-off-by: Rob Clark robdclark@chromium.org --- This is a quick implementation of what I had in mind for driver side of deadline boost. For a couple games with bad gpu devfreq behavior this boosts "Render quality" from ~35% to ~95%. (The "Render quality" metric in chrome://arc-overview-tracing is basically a measure of the deviation in frame/commit time, so 100% would be a consistent fps with no variantion.) Not quite 100%, this is still a bit of a re- active mechanism.
A similar result can be had by tuning devfreq to boost to max OPP at a much lower threshold of busyness. With the obvious downside that you spend a lot of time running the GPU much faster than needed.
drivers/gpu/drm/msm/msm_fence.c | 76 +++++++++++++++++++++++++++ drivers/gpu/drm/msm/msm_fence.h | 20 +++++++ drivers/gpu/drm/msm/msm_gpu.h | 1 + drivers/gpu/drm/msm/msm_gpu_devfreq.c | 20 +++++++ 4 files changed, 117 insertions(+)
diff --git a/drivers/gpu/drm/msm/msm_fence.c b/drivers/gpu/drm/msm/msm_fence.c index f2cece542c3f..67c2a96e1c85 100644 --- a/drivers/gpu/drm/msm/msm_fence.c +++ b/drivers/gpu/drm/msm/msm_fence.c @@ -8,6 +8,37 @@
#include "msm_drv.h" #include "msm_fence.h" +#include "msm_gpu.h" + +static inline bool fence_completed(struct msm_fence_context *fctx, uint32_t fence); + +static struct msm_gpu *fctx2gpu(struct msm_fence_context *fctx) +{ + struct msm_drm_private *priv = fctx->dev->dev_private; + return priv->gpu; +} + +static enum hrtimer_restart deadline_timer(struct hrtimer *t) +{ + struct msm_fence_context *fctx = container_of(t, + struct msm_fence_context, deadline_timer); + + kthread_queue_work(fctx2gpu(fctx)->worker, &fctx->deadline_work); + + return HRTIMER_NORESTART; +} + +static void deadline_work(struct kthread_work *work) +{ + struct msm_fence_context *fctx = container_of(work, + struct msm_fence_context, deadline_work); + + /* If deadline fence has already passed, nothing to do: */ + if (fence_completed(fctx, fctx->next_deadline_fence)) + return; + + msm_devfreq_boost(fctx2gpu(fctx), 2); +}
struct msm_fence_context * @@ -26,6 +57,13 @@ msm_fence_context_alloc(struct drm_device *dev, volatile uint32_t *fenceptr, fctx->fenceptr = fenceptr; spin_lock_init(&fctx->spinlock);
+ hrtimer_init(&fctx->deadline_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS); + fctx->deadline_timer.function = deadline_timer; + + kthread_init_work(&fctx->deadline_work, deadline_work); + + fctx->next_deadline = ktime_get(); + return fctx; }
@@ -49,6 +87,8 @@ void msm_update_fence(struct msm_fence_context *fctx, uint32_t fence) { spin_lock(&fctx->spinlock); fctx->completed_fence = max(fence, fctx->completed_fence); + if (fence_completed(fctx, fctx->next_deadline_fence)) + hrtimer_cancel(&fctx->deadline_timer); spin_unlock(&fctx->spinlock); }
@@ -79,10 +119,46 @@ static bool msm_fence_signaled(struct dma_fence *fence) return fence_completed(f->fctx, f->base.seqno); }
+static void msm_fence_set_deadline(struct dma_fence *fence, ktime_t deadline) +{ + struct msm_fence *f = to_msm_fence(fence); + struct msm_fence_context *fctx = f->fctx; + unsigned long flags; + ktime_t now; + + spin_lock_irqsave(&fctx->spinlock, flags); + now = ktime_get(); + + if (ktime_after(now, fctx->next_deadline) || + ktime_before(deadline, fctx->next_deadline)) { + fctx->next_deadline = deadline; + fctx->next_deadline_fence = + max(fctx->next_deadline_fence, (uint32_t)fence->seqno); + + /* + * Set timer to trigger boost 3ms before deadline, or + * if we are already less than 3ms before the deadline + * schedule boost work immediately. + */ + deadline = ktime_sub(deadline, ms_to_ktime(3)); + + if (ktime_after(now, deadline)) { + kthread_queue_work(fctx2gpu(fctx)->worker, + &fctx->deadline_work); + } else { + hrtimer_start(&fctx->deadline_timer, deadline, + HRTIMER_MODE_ABS); + } + } + + spin_unlock_irqrestore(&fctx->spinlock, flags); +} + static const struct dma_fence_ops msm_fence_ops = { .get_driver_name = msm_fence_get_driver_name, .get_timeline_name = msm_fence_get_timeline_name, .signaled = msm_fence_signaled, + .set_deadline = msm_fence_set_deadline, };
struct dma_fence * diff --git a/drivers/gpu/drm/msm/msm_fence.h b/drivers/gpu/drm/msm/msm_fence.h index 4783db528bcc..d34e853c555a 100644 --- a/drivers/gpu/drm/msm/msm_fence.h +++ b/drivers/gpu/drm/msm/msm_fence.h @@ -50,6 +50,26 @@ struct msm_fence_context { volatile uint32_t *fenceptr;
spinlock_t spinlock; + + /* + * TODO this doesn't really deal with multiple deadlines, like + * if userspace got multiple frames ahead.. OTOH atomic updates + * don't queue, so maybe that is ok + */ + + /** next_deadline: Time of next deadline */ + ktime_t next_deadline; + + /** + * next_deadline_fence: + * + * Fence value for next pending deadline. The deadline timer is + * canceled when this fence is signaled. + */ + uint32_t next_deadline_fence; + + struct hrtimer deadline_timer; + struct kthread_work deadline_work; };
struct msm_fence_context * msm_fence_context_alloc(struct drm_device *dev, diff --git a/drivers/gpu/drm/msm/msm_gpu.h b/drivers/gpu/drm/msm/msm_gpu.h index 0e4b45bff2e6..e031c9b495ed 100644 --- a/drivers/gpu/drm/msm/msm_gpu.h +++ b/drivers/gpu/drm/msm/msm_gpu.h @@ -425,6 +425,7 @@ void msm_devfreq_init(struct msm_gpu *gpu); void msm_devfreq_cleanup(struct msm_gpu *gpu); void msm_devfreq_resume(struct msm_gpu *gpu); void msm_devfreq_suspend(struct msm_gpu *gpu); +void msm_devfreq_boost(struct msm_gpu *gpu, unsigned factor); void msm_devfreq_active(struct msm_gpu *gpu); void msm_devfreq_idle(struct msm_gpu *gpu);
diff --git a/drivers/gpu/drm/msm/msm_gpu_devfreq.c b/drivers/gpu/drm/msm/msm_gpu_devfreq.c index 0a1ee20296a2..8a8d7b9028a3 100644 --- a/drivers/gpu/drm/msm/msm_gpu_devfreq.c +++ b/drivers/gpu/drm/msm/msm_gpu_devfreq.c @@ -144,6 +144,26 @@ void msm_devfreq_suspend(struct msm_gpu *gpu) devfreq_suspend_device(gpu->devfreq.devfreq); }
+void msm_devfreq_boost(struct msm_gpu *gpu, unsigned factor) +{ + struct msm_gpu_devfreq *df = &gpu->devfreq; + unsigned long freq; + + /* + * Hold devfreq lock to synchronize with get_dev_status()/ + * target() callbacks + */ + mutex_lock(&df->devfreq->lock); + + freq = get_freq(gpu); + + freq *= factor; + + msm_devfreq_target(&gpu->pdev->dev, &freq, 0); + + mutex_unlock(&df->devfreq->lock); +} + void msm_devfreq_active(struct msm_gpu *gpu) { struct msm_gpu_devfreq *df = &gpu->devfreq;