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: Nirmoy Das <nirmoy.das@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
index 2e3a058fc2398b7a4414e1050986f42cd99956b4..33e2cd1089a24a48d15df9adb35cb68a81797391 100644 (file)
--- a/drivers/gpu/drm/scheduler/sched_entity.c
+++ b/drivers/gpu/drm/scheduler/sched_entity.c
@@ -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);
 

diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 3fad5876a13f2f9f8451bab08f6f38a40e32effc..71ce6215956fbc91345da32f0412410132118f8f 100644 (file)
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -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 */

diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
index 96a1a1b7526ed7d48b98d05af349f2c67473b7cf..537f7a4655a551a8eb9f982f1a4e41161f265d3d 100644 (file)
--- a/include/drm/gpu_scheduler.h
+++ b/include/drm/gpu_scheduler.h
@@ -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.
  *
@@ -282,8 +282,8 @@ struct drm_gpu_scheduler {
        struct list_head                ring_mirror_list;
        spinlock_t                      job_list_lock;
        int                             hang_limit;
-       atomic_t                        num_jobs;
-       bool                    ready;
+       atomic_t                        score;
+       bool                            ready;
        bool                            free_guilty;
 };