Commit d41a39dd authored by Nirmoy Das's avatar Nirmoy Das Committed by Christian König
Browse files

drm/scheduler: improve job distribution with multiple queues 



This patch uses score to select a new drm scheduler for better
loadbalance between multiple drm schedulers instead of num_jobs.

Below are test results after running amdgpu_test for ~10 times.

Before this patch:

sched_name     num of many times it got schedule
=========      ==================================
sdma0          1463
sdma1          198
comp_1.0.1     280

After this patch:

sched_name     num of many times it got schedule
=========      ==================================
sdma0          925
sdma1          928
comp_1.0.1     177
comp_1.1.1     44
comp_1.2.1     43
comp_1.3.1     44

Signed-off-by: default avatarNirmoy Das <nirmoy.das@amd.com>
Reviewed-by: default avatarChristian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/373000/


Signed-off-by: default avatarChristian König <christian.koenig@amd.com>
parent 0dc9b286

drivers/gpu/drm/scheduler/sched_entity.c

+1 −1
Original line number Diff line number Diff line
@@ -486,7 +486,7 @@ void drm_sched_entity_push_job(struct drm_sched_job *sched_job, 
	bool first;



	trace_drm_sched_job(sched_job, entity);

	atomic_inc(&entity->rq->sched->num_jobs);

	atomic_inc(&entity->rq->sched->score);

	WRITE_ONCE(entity->last_user, current->group_leader);

	first = spsc_queue_push(&entity->job_queue, &sched_job->queue_node);

drivers/gpu/drm/scheduler/sched_main.c

+8 −6
Original line number Diff line number Diff line
@@ -92,6 +92,7 @@ void drm_sched_rq_add_entity(struct drm_sched_rq *rq, 
	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);

}
@@ -110,6 +111,7 @@ void drm_sched_rq_remove_entity(struct drm_sched_rq *rq, 
	if (list_empty(&entity->list))

		return;

	spin_lock(&rq->lock);

	atomic_dec(&rq->sched->score);

	list_del_init(&entity->list);

	if (rq->current_entity == entity)

		rq->current_entity = NULL;
@@ -647,7 +649,7 @@ static void drm_sched_process_job(struct dma_fence *f, struct dma_fence_cb *cb) 
	struct drm_gpu_scheduler *sched = s_fence->sched;



	atomic_dec(&sched->hw_rq_count);

	atomic_dec(&sched->num_jobs);

	atomic_dec(&sched->score);



	trace_drm_sched_process_job(s_fence);
@@ -712,7 +714,7 @@ drm_sched_pick_best(struct drm_gpu_scheduler **sched_list, 
{

	struct drm_gpu_scheduler *sched, *picked_sched = NULL;

	int i;

	unsigned int min_jobs = UINT_MAX, num_jobs;

	unsigned int min_score = UINT_MAX, num_score;



	for (i = 0; i < num_sched_list; ++i) {

		sched = sched_list[i];
@@ -723,9 +725,9 @@ drm_sched_pick_best(struct drm_gpu_scheduler **sched_list, 
			continue;

		}



		num_jobs = atomic_read(&sched->num_jobs);

		if (num_jobs < min_jobs) {

			min_jobs = num_jobs;

		num_score = atomic_read(&sched->score);

		if (num_score < min_score) {

			min_score = num_score;

			picked_sched = sched;

		}

	}
@@ -860,7 +862,7 @@ int drm_sched_init(struct drm_gpu_scheduler *sched, 
	spin_lock_init(&sched->job_list_lock);

	atomic_set(&sched->hw_rq_count, 0);

	INIT_DELAYED_WORK(&sched->work_tdr, drm_sched_job_timedout);

	atomic_set(&sched->num_jobs, 0);

	atomic_set(&sched->score, 0);

	atomic64_set(&sched->job_id_count, 0);



	/* Each scheduler will run on a seperate kernel thread */

include/drm/gpu_scheduler.h

+3 −3
Original line number Diff line number Diff line
@@ -263,7 +263,7 @@ 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

 * @score: score to help loadbalancer pick a idle sched

 * @ready: marks if the underlying HW is ready to work

 * @free_guilty: A hit to time out handler to free the guilty job.

 *
@@ -284,7 +284,7 @@ struct drm_gpu_scheduler { 
	struct list_head		ring_mirror_list;

	spinlock_t			job_list_lock;

	int				hang_limit;

	atomic_t                        num_jobs;

	atomic_t                        score;

	bool				ready;

	bool				free_guilty;

};