| Message ID | 20170426144620.3560-1-andresx7@gmail.com |
|---|---|
| State | Accepted |
| Commit | 03c0c5f6641533f5fc14bf4e76d2304197402552 |
| Headers | show |
| Series |
"dma-buf: avoid scheduling on fence status query"
( rev:
2
)
in
DRI devel |
diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c index 0918d3f..57da14c 100644 --- a/drivers/dma-buf/dma-fence.c +++ b/drivers/dma-buf/dma-fence.c @@ -402,6 +402,11 @@ dma_fence_default_wait(struct dma_fence *fence, bool intr, signed long timeout) } } + if (!timeout) { + ret = 0; + goto out; + } + cb.base.func = dma_fence_default_wait_cb; cb.task = current; list_add(&cb.base.node, &fence->cb_list);
Am 26.04.2017 um 16:46 schrieb Andres Rodriguez: > 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. > > v2: move early return after enable_signaling > > Signed-off-by: Andres Rodriguez <andresx7@gmail.com> Reviewed-by: Christian König <christian.koenig@amd.com> > --- > > If I'm understanding correctly, I don't think we need to register the > default wait callback. But if that isn't the case please let me know. > > This patch has the same perf improvements as v1. > > drivers/dma-buf/dma-fence.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c > index 0918d3f..57da14c 100644 > --- a/drivers/dma-buf/dma-fence.c > +++ b/drivers/dma-buf/dma-fence.c > @@ -402,6 +402,11 @@ dma_fence_default_wait(struct dma_fence *fence, bool intr, signed long timeout) > } > } > > + if (!timeout) { > + ret = 0; > + goto out; > + } > + > cb.base.func = dma_fence_default_wait_cb; > cb.task = current; > list_add(&cb.base.node, &fence->cb_list);
2017-04-26 Christian König <deathsimple@vodafone.de>: > Am 26.04.2017 um 16:46 schrieb Andres Rodriguez: > > 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. > > > > v2: move early return after enable_signaling > > > > Signed-off-by: Andres Rodriguez <andresx7@gmail.com> > > Reviewed-by: Christian König <christian.koenig@amd.com> pushed to drm-misc-next. Thanks all. Gustavo
On 28 April 2017 at 07:27, Gustavo Padovan <gustavo@padovan.org> wrote: > 2017-04-26 Christian König <deathsimple@vodafone.de>: > >> Am 26.04.2017 um 16:46 schrieb Andres Rodriguez: >> > 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. >> > >> > v2: move early return after enable_signaling >> > >> > Signed-off-by: Andres Rodriguez <andresx7@gmail.com> >> >> Reviewed-by: Christian König <christian.koenig@amd.com> > > pushed to drm-misc-next. Thanks all. I don't see this patch in -rc2, where did it end up going? Dave.
On Wed, May 24, 2017 at 09:47:49AM +1000, Dave Airlie wrote: > On 28 April 2017 at 07:27, Gustavo Padovan <gustavo@padovan.org> wrote: > > 2017-04-26 Christian König <deathsimple@vodafone.de>: > > > >> Am 26.04.2017 um 16:46 schrieb Andres Rodriguez: > >> > 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. > >> > > >> > v2: move early return after enable_signaling > >> > > >> > Signed-off-by: Andres Rodriguez <andresx7@gmail.com> > >> > >> Reviewed-by: Christian König <christian.koenig@amd.com> > > > > pushed to drm-misc-next. Thanks all. > > I don't see this patch in -rc2, where did it end up going? Queued for 4.13. Makes imo sense since it's just a performance improvement, not a clear bugfix. But it's in your drm-next, so if you want to fast-track you can cherry-pick it over: commit 03c0c5f6641533f5fc14bf4e76d2304197402552 Author: Andres Rodriguez <andresx7@gmail.com> Date: Wed Apr 26 10:46:20 2017 -0400 dma-buf: avoid scheduling on fence status query v2 Cheers, Daniel
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. v2: move early return after enable_signaling Signed-off-by: Andres Rodriguez <andresx7@gmail.com> --- If I'm understanding correctly, I don't think we need to register the default wait callback. But if that isn't the case please let me know. This patch has the same perf improvements as v1. drivers/dma-buf/dma-fence.c | 5 +++++ 1 file changed, 5 insertions(+)