On 2023-11-02 07:13, Tvrtko Ursulin wrote:
>
> On 31/10/2023 03:24, Matthew Brost wrote:
>> Rather than call free_job and run_job in same work item have a dedicated
>> work item for each. This aligns with the design and intended use of work
>> queues.
>>
>> v2:
>> - Test for DMA_FENCE_FLAG_TIMESTAMP_BIT before setting
>> timestamp in free_job() work item (Danilo)
>> v3:
>> - Drop forward dec of drm_sched_select_entity (Boris)
>> - Return in drm_sched_run_job_work if entity NULL (Boris)
>> v4:
>> - Replace dequeue with peek and invert logic (Luben)
>> - Wrap to 100 lines (Luben)
>> - Update comments for *_queue / *_queue_if_ready functions (Luben)
>> v5:
>> - Drop peek argument, blindly reinit idle (Luben)
>> - s/drm_sched_free_job_queue_if_ready/drm_sched_free_job_queue_if_done (Luben)
>> - Update work_run_job & work_free_job kernel doc (Luben)
>> v6:
>> - Do not move drm_sched_select_entity in file (Luben)
>>
>> Signed-off-by: Matthew Brost <matthew.brost@xxxxxxxxx>
>> ---
>> drivers/gpu/drm/scheduler/sched_main.c | 146 +++++++++++++++++--------
>> include/drm/gpu_scheduler.h | 4 +-
>> 2 files changed, 101 insertions(+), 49 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
>> index d1ae05bded15..3b1b2f8eafe8 100644
>> --- a/drivers/gpu/drm/scheduler/sched_main.c
>> +++ b/drivers/gpu/drm/scheduler/sched_main.c
>> @@ -265,6 +265,32 @@ static void drm_sched_run_job_queue(struct drm_gpu_scheduler *sched)
>> queue_work(sched->submit_wq, &sched->work_run_job);
>> }
>>
>> +/**
>> + * drm_sched_free_job_queue - enqueue free-job work
>> + * @sched: scheduler instance
>> + */
>> +static void drm_sched_free_job_queue(struct drm_gpu_scheduler *sched)
>> +{
>> + if (!READ_ONCE(sched->pause_submit))
>> + queue_work(sched->submit_wq, &sched->work_free_job);
>> +}
>> +
>> +/**
>> + * drm_sched_free_job_queue_if_done - enqueue free-job work if ready
>> + * @sched: scheduler instance
>> + */
>> +static void drm_sched_free_job_queue_if_done(struct drm_gpu_scheduler *sched)
>> +{
>> + struct drm_sched_job *job;
>> +
>> + spin_lock(&sched->job_list_lock);
>> + job = list_first_entry_or_null(&sched->pending_list,
>> + struct drm_sched_job, list);
>> + if (job && dma_fence_is_signaled(&job->s_fence->finished))
>> + drm_sched_free_job_queue(sched);
>> + spin_unlock(&sched->job_list_lock);
>> +}
>> +
>> /**
>> * drm_sched_job_done - complete a job
>> * @s_job: pointer to the job which is done
>> @@ -284,7 +310,7 @@ static void drm_sched_job_done(struct drm_sched_job *s_job, int result)
>> dma_fence_get(&s_fence->finished);
>> drm_sched_fence_finished(s_fence, result);
>> dma_fence_put(&s_fence->finished);
>> - drm_sched_run_job_queue(sched);
>> + drm_sched_free_job_queue(sched);
>> }
>>
>> /**
>> @@ -943,8 +969,10 @@ drm_sched_get_cleanup_job(struct drm_gpu_scheduler *sched)
>> typeof(*next), list);
>>
>> if (next) {
>> - next->s_fence->scheduled.timestamp =
>> - dma_fence_timestamp(&job->s_fence->finished);
>> + if (test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT,
>> + &next->s_fence->scheduled.flags))
>> + next->s_fence->scheduled.timestamp =
>> + dma_fence_timestamp(&job->s_fence->finished);
>> /* start TO timer for next job */
>> drm_sched_start_timeout(sched);
>> }
>> @@ -994,7 +1022,40 @@ drm_sched_pick_best(struct drm_gpu_scheduler **sched_list,
>> EXPORT_SYMBOL(drm_sched_pick_best);
>>
>> /**
>> - * drm_sched_run_job_work - main scheduler thread
>> + * drm_sched_run_job_queue_if_ready - enqueue run-job work if ready
>> + * @sched: scheduler instance
>> + */
>> +static void drm_sched_run_job_queue_if_ready(struct drm_gpu_scheduler *sched)
>> +{
>> + if (drm_sched_select_entity(sched))
>> + drm_sched_run_job_queue(sched);
>> +}
>> +
>> +/**
>> + * drm_sched_free_job_work - worker to call free_job
>> + *
>> + * @w: free job work
>> + */
>> +static void drm_sched_free_job_work(struct work_struct *w)
>> +{
>> + struct drm_gpu_scheduler *sched =
>> + container_of(w, struct drm_gpu_scheduler, work_free_job);
>> + struct drm_sched_job *cleanup_job;
>> +
>> + if (READ_ONCE(sched->pause_submit))
>> + return;
>> +
>> + cleanup_job = drm_sched_get_cleanup_job(sched);
>> + if (cleanup_job) {
>> + sched->ops->free_job(cleanup_job);
>> +
>> + drm_sched_free_job_queue_if_done(sched);
>> + drm_sched_run_job_queue_if_ready(sched);
>
> Are finished jobs now disturbing the round robin selection?
>
> Every time this cleans up a job we get:
>
> drm_sched_run_job_queue_if_ready
> -> drm_sched_select_entity
> -> drm_sched_rq_select_entity_rr
> -> rq->current_entity bumped to next in list
>
> So when the job run worker does:
>
> entity = drm_sched_select_entity(sched);
>
> It does not pick the same entity as before this patch? If so perhaps
> drm_sched_run_job_queue_if_ready needs a "peek" helper which does not
> modify any state.
Hi Tvrtko,
Thank you for reporting this. I've sent out a patch.
--
Regards,
Luben
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