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 andresx7@gmail.com

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)) {