From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andres Rodriguez Subject: Re: [PATCH] dma-buf: avoid scheduling on fence status query Date: Tue, 25 Apr 2017 22:50:27 -0400 Message-ID: References: <20170426013632.4716-1-andresx7@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20170426013632.4716-1-andresx7@gmail.com> Sender: linux-media-owner@vger.kernel.org To: dri-devel@lists.freedesktop.org Cc: deathsimple@vodafone.de, linaro-mm-sig@lists.linaro.org, sumit.semwal@linaro.org, linux-media@vger.kernel.org List-Id: dri-devel@lists.freedesktop.org CC a few extra lists I missed. Regards, Andres On 2017-04-25 09:36 PM, Andres Rodriguez wrote: > When a timeout of zero is specified, the caller is only interested in > the fence status. > > In the current implementation, dma_fence_default_wait will always call > schedule_timeout() at least once for an unsignaled fence. This adds a > significant overhead to a fence status query. > > Avoid this overhead by returning early if a zero timeout is specified. > > Signed-off-by: Andres Rodriguez > --- > > This heavily affects the performance of the Source2 engine running on > radv. > > This patch improves dota2(radv) perf on a i7-6700k+RX480 system from > 72fps->81fps. > > drivers/dma-buf/dma-fence.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c > index 0918d3f..348e9e2 100644 > --- a/drivers/dma-buf/dma-fence.c > +++ b/drivers/dma-buf/dma-fence.c > @@ -380,6 +380,9 @@ dma_fence_default_wait(struct dma_fence *fence, bool intr, signed long timeout) > if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) > return ret; > > + if (!timeout) > + return 0; > + > spin_lock_irqsave(fence->lock, flags); > > if (intr && signal_pending(current)) { >