[Intel-gfx] [PATCH i-g-t] i915/perf_pmu: Update inter-engine semaphore detection

[Intel-gfx] [PATCH i-g-t] i915/perf_pmu: Update inter-engine semaphore detection

[Chris Wilson]

The kernel no longer uses semaphores between engines, unless it can do
so by preempting them with timeslices. Update the semaphore-busy to only
run when we expect semaphore usage, i.e. not on bdw/bsw.

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/1939
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 tests/perf_pmu.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tests/perf_pmu.c b/tests/perf_pmu.c
index e54a0d47e..e80f730cf 100644
--- a/tests/perf_pmu.c
+++ b/tests/perf_pmu.c
@@ -822,6 +822,7 @@ sema_busy(int gem_fd,
 	int fd;
 
 	igt_require(gem_scheduler_has_semaphores(gem_fd));
+	igt_require(gem_scheduler_has_preemption(gem_fd));
 
 	fd = open_group(gem_fd,
 			I915_PMU_ENGINE_SEMA(e->class, e->instance), -1);
-- 
2.27.0.rc0

_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

Re: [Intel-gfx] [PATCH i-g-t] i915/perf_pmu: Update inter-engine semaphore detection

[Tvrtko Ursulin]

On 26/05/2020 15:17, Chris Wilson wrote:
> The kernel no longer uses semaphores between engines, unless it can do
> so by preempting them with timeslices. Update the semaphore-busy to only
> run when we expect semaphore usage, i.e. not on bdw/bsw.
> 
> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/1939
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> ---
>   tests/perf_pmu.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/tests/perf_pmu.c b/tests/perf_pmu.c
> index e54a0d47e..e80f730cf 100644
> --- a/tests/perf_pmu.c
> +++ b/tests/perf_pmu.c
> @@ -822,6 +822,7 @@ sema_busy(int gem_fd,
>   	int fd;
>   
>   	igt_require(gem_scheduler_has_semaphores(gem_fd));
> +	igt_require(gem_scheduler_has_preemption(gem_fd));
>   
>   	fd = open_group(gem_fd,
>   			I915_PMU_ENGINE_SEMA(e->class, e->instance), -1);
> 

Test with perhaps too intimate knowledge of i915..

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

Regards,

Tvrtko
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

Re: [Intel-gfx] [PATCH i-g-t] i915/perf_pmu: Update inter-engine semaphore detection

[Chris Wilson]

Quoting Tvrtko Ursulin (2020-05-26 16:58:05)
> 
> On 26/05/2020 15:17, Chris Wilson wrote:
> > The kernel no longer uses semaphores between engines, unless it can do
> > so by preempting them with timeslices. Update the semaphore-busy to only
> > run when we expect semaphore usage, i.e. not on bdw/bsw.
> > 
> > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/1939
> > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> > ---
> >   tests/perf_pmu.c | 1 +
> >   1 file changed, 1 insertion(+)
> > 
> > diff --git a/tests/perf_pmu.c b/tests/perf_pmu.c
> > index e54a0d47e..e80f730cf 100644
> > --- a/tests/perf_pmu.c
> > +++ b/tests/perf_pmu.c
> > @@ -822,6 +822,7 @@ sema_busy(int gem_fd,
> >       int fd;
> >   
> >       igt_require(gem_scheduler_has_semaphores(gem_fd));
> > +     igt_require(gem_scheduler_has_preemption(gem_fd));
> >   
> >       fd = open_group(gem_fd,
> >                       I915_PMU_ENGINE_SEMA(e->class, e->instance), -1);
> > 
> 
> Test with perhaps too intimate knowledge of i915..

iirc, part of the intent of the test was to understand how the kernel's
choice of inter-engine sync would show up in the pmu. The challenge we
have is in declaring the expected outcomes, that requires intimate
knowledge of what the kernel might decide to do.
-Chris
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx