On Thu, Aug 2, 2018 at 11:29 AM Zhang, Jerry (Junwei) <Jerry.Zhang@xxxxxxx> wrote:
On 08/02/2018 01:50 PM, Nayan Deshmukh wrote:
>
>
> On Thu, Aug 2, 2018 at 10:31 AM Zhang, Jerry (Junwei) <Jerry.Zhang@xxxxxxx <mailto:Jerry.Zhang@xxxxxxx>> wrote:
>
> On 07/12/2018 02:36 PM, Nayan Deshmukh wrote:
> > Signed-off-by: Nayan Deshmukh <nayan26deshmukh@xxxxxxxxx <mailto:nayan26deshmukh@xxxxxxxxx>>
> > ---
> > drivers/gpu/drm/scheduler/gpu_scheduler.c | 3 +++
> > include/drm/gpu_scheduler.h | 2 ++
> > 2 files changed, 5 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/scheduler/gpu_scheduler.c b/drivers/gpu/drm/scheduler/gpu_scheduler.c
> > index 429b1328653a..3dc1a4f07e3f 100644
> > --- a/drivers/gpu/drm/scheduler/gpu_scheduler.c
> > +++ b/drivers/gpu/drm/scheduler/gpu_scheduler.c
> > @@ -538,6 +538,7 @@ void drm_sched_entity_push_job(struct drm_sched_job *sched_job,
> > trace_drm_sched_job(sched_job, entity);
> >
> > first = spsc_queue_push(&entity->job_queue, &sched_job->queue_node);
> > + atomic_inc(&entity->sched->num_jobs);
>
> Shall we use hw_rq_count directly or merge them together?
>
> hw_rq_count is the number of jobs that are currently in the hardware queue as compared to num_jobs which is the number of jobs in the software queue. num_jobs provides a give a better idea of the load
> on a scheduler that's why I added that field and used it to decide the scheduler with the least load.
Thanks for your explanation.
Then may be more reasonable to move atomic_dec(&sched->num_jobs) after drm_sched_fence_scheduled() or just before atomic_inc(&sched->hw_rq_count).
How do you think that?
For now num_jobs also includes jobs that have been pushed to the hardware queue. If I shift it before atomic_inc(&sched->hw_rq_count) then I also need to handle cases when the job was reset and update the counter properly. I went for the easier implementation as I felt that num_jobs will correctly represent the load on the scheduler.
But the idea that you suggested can be a potential improvement over what I have done.
Regards,
Nayan
Regards,
Jerry
>
> Regards,
> Nayan
>
>
> Regards,
> Jerry
> >
> > /* first job wakes up scheduler */
> > if (first) {
> > @@ -818,6 +819,7 @@ static void drm_sched_process_job(struct dma_fence *f, struct dma_fence_cb *cb)
> >
> > dma_fence_get(&s_fence->finished);
> > atomic_dec(&sched->hw_rq_count);
> > + atomic_dec(&sched->num_jobs);
> > drm_sched_fence_finished(s_fence);
> >
> > trace_drm_sched_process_job(s_fence);
> > @@ -935,6 +937,7 @@ int drm_sched_init(struct drm_gpu_scheduler *sched,
> > INIT_LIST_HEAD(&sched->ring_mirror_list);
> > spin_lock_init(&sched->job_list_lock);
> > atomic_set(&sched->hw_rq_count, 0);
> > + atomic_set(&sched->num_jobs, 0);
> > atomic64_set(&sched->job_id_count, 0);
> >
> > /* Each scheduler will run on a seperate kernel thread */
> > diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
> > index 43e93d6077cf..605bd4ad2397 100644
> > --- a/include/drm/gpu_scheduler.h
> > +++ b/include/drm/gpu_scheduler.h
> > @@ -257,6 +257,7 @@ struct drm_sched_backend_ops {
> > * @job_list_lock: lock to protect the ring_mirror_list.
> > * @hang_limit: once the hangs by a job crosses this limit then it is marked
> > * guilty and it will be considered for scheduling further.
> > + * @num_jobs: the number of jobs in queue in the scheduler
> > *
> > * One scheduler is implemented for each hardware ring.
> > */
> > @@ -274,6 +275,7 @@ struct drm_gpu_scheduler {
> > struct list_head ring_mirror_list;
> > spinlock_t job_list_lock;
> > int hang_limit;
> > + atomic_t num_jobs;
> > };
> >
> > int drm_sched_init(struct drm_gpu_scheduler *sched,
> >
>
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