Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> writes: > Quoting Mika Kuoppala (2020-05-08 10:57:37) >> Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> writes: >> >> > While we ordinarily do not skip submit-fences due to the accompanying >> > hook that we want to callback on execution, a submit-fence on the same >> > timeline is meaningless. >> > >> > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> >> > Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> >> > --- >> > drivers/gpu/drm/i915/i915_request.c | 3 +++ >> > 1 file changed, 3 insertions(+) >> > >> > diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c >> > index 589739bfee25..be2ce9065a29 100644 >> > --- a/drivers/gpu/drm/i915/i915_request.c >> > +++ b/drivers/gpu/drm/i915/i915_request.c >> > @@ -1242,6 +1242,9 @@ i915_request_await_execution(struct i915_request *rq, >> > continue; >> > } >> > >> > + if (fence->context == rq->fence.context) >> > + continue; >> > + >> > /* >> > * We don't squash repeated fence dependencies here as we >> > * want to run our callback in all cases. >> >> The comment in here makes me nervous. Is this skipping on same context >> other than squashing? > > The hooks we have only apply between timelines, so skipping isn't an > issue. Suppressing the wait ensures that > > syncobj-future-submit-past: > I915_EXEC_FENCE_WAIT | > I915_EXEC_FENCE_WAIT_SUBMIT | > I915_EXEC_FENCE_SIGNAL > > is a no-op. That is if you declare that request should wait for itself > to be submitted before it is submitted, we correctly conclude that is > degenerate and a no-op. We can generalise that to realise that waiting for > any fence along the same timeline to be submitted before we are > submitted is guaranteed by the timeline itself, and so all are no-ops. The last sentence nails it. Reviewed-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx> > -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
