On Fri, Mar 3, 2023 at 2:10 AM Dmitry Baryshkov <dmitry.barysh...@linaro.org> wrote: > > On 03/03/2023 01:53, Rob Clark wrote: > > From: Rob Clark <robdcl...@chromium.org> > > > > Track the nearest deadline on a fence timeline and set a timer to expire > > shortly before to trigger boost if the fence has not yet been signaled. > > > > v2: rebase > > > > Signed-off-by: Rob Clark <robdcl...@chromium.org> > > --- > > drivers/gpu/drm/msm/msm_fence.c | 74 +++++++++++++++++++++++++++++++++ > > drivers/gpu/drm/msm/msm_fence.h | 20 +++++++++ > > 2 files changed, 94 insertions(+) > > Reviewed-by: Dmitry Baryshkov <dmitry.barysh...@linaro.org> > > A small question: do we boost to fit into the deadline or to miss the > deadline for as little as possible? If the former is the case, we might > need to adjust 3ms depending on the workload.
The goal is as much to run with higher clock on the next frame as it is to not miss a deadline. Ie. we don't want devfreq to come to the conclusion that running at <50% clks is best due to the amount of utilization caused by missing ever other vblank. But 3ms is mostly just "seems like a good compromise" value. It might change. BR, -R > > > > diff --git a/drivers/gpu/drm/msm/msm_fence.c > > b/drivers/gpu/drm/msm/msm_fence.c > > index 56641408ea74..51b461f32103 100644 > > --- a/drivers/gpu/drm/msm/msm_fence.c > > +++ b/drivers/gpu/drm/msm/msm_fence.c > > @@ -8,6 +8,35 @@ > > > > #include "msm_drv.h" > > #include "msm_fence.h" > > +#include "msm_gpu.h" > > + > > +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 (msm_fence_completed(fctx, fctx->next_deadline_fence)) > > + return; > > + > > + msm_devfreq_boost(fctx2gpu(fctx), 2); > > +} > > > > > > struct msm_fence_context * > > @@ -36,6 +65,13 @@ msm_fence_context_alloc(struct drm_device *dev, volatile > > uint32_t *fenceptr, > > fctx->completed_fence = fctx->last_fence; > > *fctx->fenceptr = fctx->last_fence; > > > > + 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; > > } > > > > @@ -62,6 +98,8 @@ void msm_update_fence(struct msm_fence_context *fctx, > > uint32_t fence) > > spin_lock_irqsave(&fctx->spinlock, flags); > > if (fence_after(fence, fctx->completed_fence)) > > fctx->completed_fence = fence; > > + if (msm_fence_completed(fctx, fctx->next_deadline_fence)) > > + hrtimer_cancel(&fctx->deadline_timer); > > spin_unlock_irqrestore(&fctx->spinlock, flags); > > } > > > > @@ -92,10 +130,46 @@ static bool msm_fence_signaled(struct dma_fence *fence) > > return msm_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 7f1798c54cd1..cdaebfb94f5c 100644 > > --- a/drivers/gpu/drm/msm/msm_fence.h > > +++ b/drivers/gpu/drm/msm/msm_fence.h > > @@ -52,6 +52,26 @@ 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, > > -- > With best wishes > Dmitry >