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)) {