[PATCH v2] drm/sched: Further optimise drm_sched_entity_push_job

Christian König ckoenig.leichtzumerken at gmail.com
Tue Sep 24 12:02:51 UTC 2024


Am 24.09.24 um 11:58 schrieb Tvrtko Ursulin:
>
> On 24/09/2024 10:45, Tvrtko Ursulin wrote:
>>
>> On 24/09/2024 09:20, Christian König wrote:
>>> Am 16.09.24 um 19:30 schrieb Tvrtko Ursulin:
>>>> From: Tvrtko Ursulin <tvrtko.ursulin at igalia.com>
>>>>
>>>> Having removed one re-lock cycle on the entity->lock in a patch titled
>>>> "drm/sched: Optimise drm_sched_entity_push_job", with only a tiny bit
>>>> larger refactoring we can do the same optimisation on the rq->lock.
>>>> (Currently both drm_sched_rq_add_entity() and
>>>> drm_sched_rq_update_fifo_locked() take and release the same lock.)
>>>>
>>>> To achieve this we make drm_sched_rq_update_fifo_locked() and
>>>> drm_sched_rq_add_entity() expect the rq->lock to be held.
>>>>
>>>> We also align drm_sched_rq_update_fifo_locked(),
>>>> drm_sched_rq_add_entity() and
>>>> drm_sched_rq_remove_fifo_locked() function signatures, by adding rq 
>>>> as a
>>>> parameter to the latter.
>>>>
>>>> v2:
>>>>   * Fix after rebase of the series.
>>>>   * Avoid naming incosistency between drm_sched_rq_add/remove. 
>>>> (Christian)
>>>>
>>>> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at igalia.com>
>>>> Cc: Christian König <christian.koenig at amd.com>
>>>> Cc: Alex Deucher <alexander.deucher at amd.com>
>>>> Cc: Luben Tuikov <ltuikov89 at gmail.com>
>>>> Cc: Matthew Brost <matthew.brost at intel.com>
>>>> Cc: Philipp Stanner <pstanner at redhat.com>
>>>
>>> Reviewed-by: Christian König <christian.koenig at amd.com>
>>
>> Thanks!
>>
>> Are you okay to pull into drm-misc-next or we should do some more 
>> testing on this?
>>
>> And/or should I resend the series once more in it's entirety so this 
>> v2 is not a reply-to to the original?
>
> I have to respin for the drm_sched_wakeup fix that landed.

When I should push the series to drm-misc-next then please send it to me 
once more.

On the other hand we should now have to maintainers for that.

Regards,
Christian.

>
> Regards,
>
> Tvrtko
>
>>
>> Regards,
>>
>> Tvrtko
>>
>>>
>>>> ---
>>>>   drivers/gpu/drm/scheduler/sched_entity.c | 12 ++++++++--
>>>>   drivers/gpu/drm/scheduler/sched_main.c   | 29 
>>>> ++++++++++++------------
>>>>   include/drm/gpu_scheduler.h              |  3 ++-
>>>>   3 files changed, 26 insertions(+), 18 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/scheduler/sched_entity.c 
>>>> b/drivers/gpu/drm/scheduler/sched_entity.c
>>>> index d982cebc6bee..8ace1f1ea66b 100644
>>>> --- a/drivers/gpu/drm/scheduler/sched_entity.c
>>>> +++ b/drivers/gpu/drm/scheduler/sched_entity.c
>>>> @@ -515,9 +515,14 @@ struct drm_sched_job 
>>>> *drm_sched_entity_pop_job(struct drm_sched_entity *entity)
>>>>           next = 
>>>> to_drm_sched_job(spsc_queue_peek(&entity->job_queue));
>>>>           if (next) {
>>>> +            struct drm_sched_rq *rq;
>>>> +
>>>>               spin_lock(&entity->lock);
>>>> -            drm_sched_rq_update_fifo_locked(entity,
>>>> +            rq = entity->rq;
>>>> +            spin_lock(&rq->lock);
>>>> +            drm_sched_rq_update_fifo_locked(entity, rq,
>>>>                               next->submit_ts);
>>>> +            spin_unlock(&rq->lock);
>>>>               spin_unlock(&entity->lock);
>>>>           }
>>>>       }
>>>> @@ -618,11 +623,14 @@ void drm_sched_entity_push_job(struct 
>>>> drm_sched_job *sched_job)
>>>>           sched = rq->sched;
>>>>           atomic_inc(sched->score);
>>>> +
>>>> +        spin_lock(&rq->lock);
>>>>           drm_sched_rq_add_entity(rq, entity);
>>>>           if (drm_sched_policy == DRM_SCHED_POLICY_FIFO)
>>>> -            drm_sched_rq_update_fifo_locked(entity, submit_ts);
>>>> +            drm_sched_rq_update_fifo_locked(entity, rq, submit_ts);
>>>> +        spin_unlock(&rq->lock);
>>>>           spin_unlock(&entity->lock);
>>>>           drm_sched_wakeup(sched, entity);
>>>> diff --git a/drivers/gpu/drm/scheduler/sched_main.c 
>>>> b/drivers/gpu/drm/scheduler/sched_main.c
>>>> index 18a952f73ecb..5c83fb92bb89 100644
>>>> --- a/drivers/gpu/drm/scheduler/sched_main.c
>>>> +++ b/drivers/gpu/drm/scheduler/sched_main.c
>>>> @@ -153,17 +153,18 @@ static __always_inline bool 
>>>> drm_sched_entity_compare_before(struct rb_node *a,
>>>>       return ktime_before(ent_a->oldest_job_waiting, 
>>>> ent_b->oldest_job_waiting);
>>>>   }
>>>> -static inline void drm_sched_rq_remove_fifo_locked(struct 
>>>> drm_sched_entity *entity)
>>>> +static void drm_sched_rq_remove_fifo_locked(struct 
>>>> drm_sched_entity *entity,
>>>> +                        struct drm_sched_rq *rq)
>>>>   {
>>>> -    struct drm_sched_rq *rq = entity->rq;
>>>> -
>>>>       if (!RB_EMPTY_NODE(&entity->rb_tree_node)) {
>>>>           rb_erase_cached(&entity->rb_tree_node, &rq->rb_tree_root);
>>>>           RB_CLEAR_NODE(&entity->rb_tree_node);
>>>>       }
>>>>   }
>>>> -void drm_sched_rq_update_fifo_locked(struct drm_sched_entity 
>>>> *entity, ktime_t ts)
>>>> +void drm_sched_rq_update_fifo_locked(struct drm_sched_entity *entity,
>>>> +                     struct drm_sched_rq *rq,
>>>> +                     ktime_t ts)
>>>>   {
>>>>       /*
>>>>        * Both locks need to be grabbed, one to protect from 
>>>> entity->rq change
>>>> @@ -171,17 +172,14 @@ void drm_sched_rq_update_fifo_locked(struct 
>>>> drm_sched_entity *entity, ktime_t ts
>>>>        * other to update the rb tree structure.
>>>>        */
>>>>       lockdep_assert_held(&entity->lock);
>>>> +    lockdep_assert_held(&rq->lock);
>>>> -    spin_lock(&entity->rq->lock);
>>>> -
>>>> -    drm_sched_rq_remove_fifo_locked(entity);
>>>> +    drm_sched_rq_remove_fifo_locked(entity, rq);
>>>>       entity->oldest_job_waiting = ts;
>>>> -    rb_add_cached(&entity->rb_tree_node, &entity->rq->rb_tree_root,
>>>> +    rb_add_cached(&entity->rb_tree_node, &rq->rb_tree_root,
>>>>                 drm_sched_entity_compare_before);
>>>> -
>>>> -    spin_unlock(&entity->rq->lock);
>>>>   }
>>>>   /**
>>>> @@ -213,15 +211,14 @@ static void drm_sched_rq_init(struct 
>>>> drm_gpu_scheduler *sched,
>>>>   void drm_sched_rq_add_entity(struct drm_sched_rq *rq,
>>>>                    struct drm_sched_entity *entity)
>>>>   {
>>>> +    lockdep_assert_held(&entity->lock);
>>>> +    lockdep_assert_held(&rq->lock);
>>>> +
>>>>       if (!list_empty(&entity->list))
>>>>           return;
>>>> -    spin_lock(&rq->lock);
>>>> -
>>>>       atomic_inc(rq->sched->score);
>>>>       list_add_tail(&entity->list, &rq->entities);
>>>> -
>>>> -    spin_unlock(&rq->lock);
>>>>   }
>>>>   /**
>>>> @@ -235,6 +232,8 @@ void drm_sched_rq_add_entity(struct 
>>>> drm_sched_rq *rq,
>>>>   void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
>>>>                   struct drm_sched_entity *entity)
>>>>   {
>>>> +    lockdep_assert_held(&entity->lock);
>>>> +
>>>>       if (list_empty(&entity->list))
>>>>           return;
>>>> @@ -247,7 +246,7 @@ void drm_sched_rq_remove_entity(struct 
>>>> drm_sched_rq *rq,
>>>>           rq->current_entity = NULL;
>>>>       if (drm_sched_policy == DRM_SCHED_POLICY_FIFO)
>>>> -        drm_sched_rq_remove_fifo_locked(entity);
>>>> +        drm_sched_rq_remove_fifo_locked(entity, rq);
>>>>       spin_unlock(&rq->lock);
>>>>   }
>>>> diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
>>>> index 80198e6cf537..b21806d5a8eb 100644
>>>> --- a/include/drm/gpu_scheduler.h
>>>> +++ b/include/drm/gpu_scheduler.h
>>>> @@ -596,7 +596,8 @@ void drm_sched_rq_add_entity(struct 
>>>> drm_sched_rq *rq,
>>>>   void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
>>>>                   struct drm_sched_entity *entity);
>>>> -void drm_sched_rq_update_fifo_locked(struct drm_sched_entity 
>>>> *entity, ktime_t ts);
>>>> +void drm_sched_rq_update_fifo_locked(struct drm_sched_entity *entity,
>>>> +                     struct drm_sched_rq *rq, ktime_t ts);
>>>>   int drm_sched_entity_init(struct drm_sched_entity *entity,
>>>>                 enum drm_sched_priority priority,
>>>



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