On Thu, Aug 10, 2023 at 8:06 PM Danilo Krummrich <d...@redhat.com> wrote:
> If a sched job depends on a dma-fence from a job from the same GPU > scheduler instance, but a different scheduler entity, the GPU scheduler > does only wait for the particular job to be scheduled, rather than for > the job to fully complete. This is due to the GPU scheduler assuming > that there is a scheduler instance per ring. However, the current > implementation, in order to avoid arbitrary amounts of kthreads, has a > single scheduler instance while scheduler entities represent rings. > > As a workaround, set the DRM_SCHED_FENCE_DONT_PIPELINE for all > out-fences in order to force the scheduler to wait for full job > completion for dependent jobs from different entities and same scheduler > instance. > > There is some work in progress [1] to address the issues of firmware > schedulers; once it is in-tree the scheduler topology in Nouveau should > be re-worked accordingly. > > [1] > https://lore.kernel.org/dri-devel/20230801205103.627779-1-matthew.br...@intel.com/ > > Signed-off-by: Danilo Krummrich <d...@redhat.com> > --- > drivers/gpu/drm/nouveau/nouveau_sched.c | 22 ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) > > diff --git a/drivers/gpu/drm/nouveau/nouveau_sched.c > b/drivers/gpu/drm/nouveau/nouveau_sched.c > index 3424a1bf6af3..88217185e0f3 100644 > --- a/drivers/gpu/drm/nouveau/nouveau_sched.c > +++ b/drivers/gpu/drm/nouveau/nouveau_sched.c > @@ -292,6 +292,28 @@ nouveau_job_submit(struct nouveau_job *job) > if (job->sync) > done_fence = dma_fence_get(job->done_fence); > > + /* If a sched job depends on a dma-fence from a job from the same > GPU > + * scheduler instance, but a different scheduler entity, the GPU > + * scheduler does only wait for the particular job to be scheduled, > s/does only wait/only waits/ Reviewed-by: Faith Ekstrand <faith.ekstrand@collaboralcom> + * rather than for the job to fully complete. This is due to the GPU > + * scheduler assuming that there is a scheduler instance per ring. > + * However, the current implementation, in order to avoid arbitrary > + * amounts of kthreads, has a single scheduler instance while > scheduler > + * entities represent rings. > + * > + * As a workaround, set the DRM_SCHED_FENCE_DONT_PIPELINE for all > + * out-fences in order to force the scheduler to wait for full job > + * completion for dependent jobs from different entities and same > + * scheduler instance. > + * > + * There is some work in progress [1] to address the issues of > firmware > + * schedulers; once it is in-tree the scheduler topology in Nouveau > + * should be re-worked accordingly. > + * > + * [1] > https://lore.kernel.org/dri-devel/20230801205103.627779-1-matthew.br...@intel.com/ > + */ > + set_bit(DRM_SCHED_FENCE_DONT_PIPELINE, &job->done_fence->flags); > + > if (job->ops->armed_submit) > job->ops->armed_submit(job); > > > base-commit: 68132cc6d1bcbc78ade524c6c6c226de42139f0e > -- > 2.41.0 > >
