Commit 56822db1 authored by Nirmoy Das's avatar Nirmoy Das Committed by Alex Deucher
Browse files

drm/scheduler: improve job distribution with multiple queues 



This patch uses score based logic to select a new rq for better
loadbalance between multiple rq/scheds instead of num_jobs.

Below are test results after running amdgpu_test from mesa drm

Before this patch:

sched_name     num of many times it got scheduled
=========      ==================================
sdma0          314
sdma1          32
comp_1.0.0     56
comp_1.0.1     0
comp_1.1.0     0
comp_1.1.1     0
comp_1.2.0     0
comp_1.2.1     0
comp_1.3.0     0
comp_1.3.1     0
After this patch:

sched_name     num of many times it got scheduled
=========      ==================================
sdma0          216
sdma1          185
comp_1.0.0     39
comp_1.0.1     9
comp_1.1.0     12
comp_1.1.1     0
comp_1.2.0     12
comp_1.2.1     0
comp_1.3.0     12
comp_1.3.1     0

Signed-off-by: default avatarNirmoy Das <nirmoy.das@amd.com>
Reviewed-by: default avatarChristian König <christian.koenig@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent 0c0dab86

drivers/gpu/drm/scheduler/sched_entity.c

+5 −5
Original line number Diff line number Diff line
@@ -130,7 +130,7 @@ static struct drm_sched_rq * 
drm_sched_entity_get_free_sched(struct drm_sched_entity *entity)

{

	struct drm_sched_rq *rq = NULL;

	unsigned int min_jobs = UINT_MAX, num_jobs;

	unsigned int min_score = UINT_MAX, num_score;

	int i;



	for (i = 0; i < entity->num_sched_list; ++i) {
@@ -141,9 +141,9 @@ drm_sched_entity_get_free_sched(struct drm_sched_entity *entity) 
			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;

			rq = &entity->sched_list[i]->sched_rq[entity->priority];

		}

	}
@@ -498,7 +498,7 @@ 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

+4 −2
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;
@@ -655,7 +657,7 @@ 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);
@@ -830,7 +832,7 @@ 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
@@ -261,7 +261,7 @@ 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.

 *
@@ -282,7 +282,7 @@ 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;

};

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