@@ -71,6 +71,8 @@ int drm_sched_entity_init(struct drm_sched_entity *entity,
entity->guilty = guilty;
entity->num_sched_list = num_sched_list;
entity->priority = priority;
+ entity->rq_priority = drm_sched_policy == DRM_SCHED_POLICY_DEADLINE ?
+ DRM_SCHED_PRIORITY_KERNEL : priority;
/*
* It's perfectly valid to initialize an entity without having a valid
* scheduler attached. It's just not valid to use the scheduler before it
@@ -87,17 +89,23 @@ int drm_sched_entity_init(struct drm_sched_entity *entity,
*/
pr_warn("%s: called with uninitialized scheduler\n", __func__);
} else if (num_sched_list) {
- /* The "priority" of an entity cannot exceed the number of run-queues of a
- * scheduler. Protect against num_rqs being 0, by converting to signed. Choose
- * the lowest priority available.
+ enum drm_sched_priority p = entity->priority;
+
+ /*
+ * The "priority" of an entity cannot exceed the number of
+ * run-queues of a scheduler. Protect against num_rqs being 0,
+ * by converting to signed. Choose the lowest priority
+ * available.
*/
- if (entity->priority >= sched_list[0]->num_rqs) {
- drm_err(sched_list[0], "entity with out-of-bounds priority:%u num_rqs:%u\n",
- entity->priority, sched_list[0]->num_rqs);
- entity->priority = max_t(s32, (s32) sched_list[0]->num_rqs - 1,
- (s32) DRM_SCHED_PRIORITY_KERNEL);
+ if (p >= sched_list[0]->num_user_rqs) {
+ drm_err(sched_list[0], "entity with out-of-bounds priority:%u num_user_rqs:%u\n",
+ p, sched_list[0]->num_user_rqs);
+ p = max_t(s32,
+ (s32)sched_list[0]->num_user_rqs - 1,
+ (s32)DRM_SCHED_PRIORITY_KERNEL);
+ entity->priority = p;
}
- entity->rq = sched_list[0]->sched_rq[entity->priority];
+ entity->rq = sched_list[0]->sched_rq[entity->rq_priority];
}
init_completion(&entity->entity_idle);
@@ -402,6 +410,27 @@ void drm_sched_entity_set_priority(struct drm_sched_entity *entity,
}
EXPORT_SYMBOL(drm_sched_entity_set_priority);
+static ktime_t
+__drm_sched_entity_get_job_deadline(struct drm_sched_entity *entity,
+ ktime_t submit_ts)
+{
+ static const unsigned int d_us[] = {
+ [DRM_SCHED_PRIORITY_KERNEL] = 100,
+ [DRM_SCHED_PRIORITY_HIGH] = 1000,
+ [DRM_SCHED_PRIORITY_NORMAL] = 5000,
+ [DRM_SCHED_PRIORITY_LOW] = 100000,
+ };
+
+ return ktime_add_us(submit_ts, d_us[entity->priority]);
+}
+
+ktime_t
+drm_sched_entity_get_job_deadline(struct drm_sched_entity *entity,
+ struct drm_sched_job *job)
+{
+ return __drm_sched_entity_get_job_deadline(entity, job->submit_ts);
+}
+
/*
* Add a callback to the current dependency of the entity to wake up the
* scheduler when the entity becomes available.
@@ -546,7 +575,7 @@ void drm_sched_entity_select_rq(struct drm_sched_entity *entity)
spin_lock(&entity->lock);
sched = drm_sched_pick_best(entity->sched_list, entity->num_sched_list);
- rq = sched ? sched->sched_rq[entity->priority] : NULL;
+ rq = sched ? sched->sched_rq[entity->rq_priority] : NULL;
if (rq != entity->rq) {
drm_sched_rq_remove_entity(entity->rq, entity);
entity->rq = rq;
@@ -588,6 +617,10 @@ void drm_sched_entity_push_job(struct drm_sched_job *sched_job)
if (first) {
struct drm_gpu_scheduler *sched;
+ if (drm_sched_policy == DRM_SCHED_POLICY_DEADLINE)
+ submit_ts = __drm_sched_entity_get_job_deadline(entity,
+ submit_ts);
+
sched = drm_sched_rq_add_entity(entity->rq, entity, submit_ts);
if (sched)
drm_sched_wakeup(sched);
@@ -87,13 +87,13 @@ static struct lockdep_map drm_sched_lockdep_map = {
};
#endif
-int drm_sched_policy = DRM_SCHED_POLICY_FIFO;
+int drm_sched_policy = DRM_SCHED_POLICY_DEADLINE;
/**
* DOC: sched_policy (int)
* Used to override default entities scheduling policy in a run queue.
*/
-MODULE_PARM_DESC(sched_policy, "Specify the scheduling policy for entities on a run-queue, " __stringify(DRM_SCHED_POLICY_RR) " = Round Robin, " __stringify(DRM_SCHED_POLICY_FIFO) " = FIFO (default).");
+MODULE_PARM_DESC(sched_policy, "Specify the scheduling policy for entities on a run-queue, " __stringify(DRM_SCHED_POLICY_RR) " = Round Robin, " __stringify(DRM_SCHED_POLICY_FIFO) " = FIFO, " __stringify(DRM_SCHED_POLICY_DEADLINE) " = Virtual deadline (default).");
module_param_named(sched_policy, drm_sched_policy, int, 0444);
static u32 drm_sched_available_credits(struct drm_gpu_scheduler *sched)
@@ -1078,11 +1078,15 @@ int drm_sched_init(struct drm_gpu_scheduler *sched,
sched->own_submit_wq = true;
}
- sched->sched_rq = kmalloc_array(num_rqs, sizeof(*sched->sched_rq),
+ sched->num_user_rqs = num_rqs;
+ sched->num_rqs = drm_sched_policy != DRM_SCHED_POLICY_DEADLINE ?
+ num_rqs : 1;
+ sched->sched_rq = kmalloc_array(sched->num_rqs,
+ sizeof(*sched->sched_rq),
GFP_KERNEL | __GFP_ZERO);
if (!sched->sched_rq)
goto Out_check_own;
- sched->num_rqs = num_rqs;
+
for (i = DRM_SCHED_PRIORITY_KERNEL; i < sched->num_rqs; i++) {
sched->sched_rq[i] = kzalloc(sizeof(*sched->sched_rq[i]), GFP_KERNEL);
if (!sched->sched_rq[i])
@@ -1196,7 +1200,7 @@ void drm_sched_increase_karma(struct drm_sched_job *bad)
if (bad->s_priority != DRM_SCHED_PRIORITY_KERNEL) {
atomic_inc(&bad->karma);
- for (i = DRM_SCHED_PRIORITY_HIGH; i < sched->num_rqs; i++) {
+ for (i = DRM_SCHED_PRIORITY_KERNEL; i < sched->num_rqs; i++) {
struct drm_sched_rq *rq = sched->sched_rq[i];
spin_lock(&rq->lock);
@@ -151,7 +151,10 @@ void drm_sched_rq_pop_entity(struct drm_sched_rq *rq,
if (next_job) {
ktime_t ts;
- if (drm_sched_policy == DRM_SCHED_POLICY_FIFO)
+ if (drm_sched_policy == DRM_SCHED_POLICY_DEADLINE)
+ ts = drm_sched_entity_get_job_deadline(entity,
+ next_job);
+ else if (drm_sched_policy == DRM_SCHED_POLICY_FIFO)
ts = next_job->submit_ts;
else
ts = drm_sched_rq_get_rr_deadline(rq);
@@ -74,8 +74,9 @@ enum drm_sched_priority {
/* Used to choose between FIFO and RR job-scheduling */
extern int drm_sched_policy;
-#define DRM_SCHED_POLICY_RR 0
-#define DRM_SCHED_POLICY_FIFO 1
+#define DRM_SCHED_POLICY_RR 0
+#define DRM_SCHED_POLICY_FIFO 1
+#define DRM_SCHED_POLICY_DEADLINE 2
/**
* struct drm_sched_entity - A wrapper around a job queue (typically
@@ -153,6 +154,8 @@ struct drm_sched_entity {
*/
struct spsc_queue job_queue;
+ enum drm_sched_priority rq_priority;
+
/**
* @fence_seq:
*
@@ -522,6 +525,7 @@ struct drm_gpu_scheduler {
long timeout;
const char *name;
u32 num_rqs;
+ u32 num_user_rqs;
struct drm_sched_rq **sched_rq;
wait_queue_head_t job_scheduled;
atomic64_t job_id_count;
@@ -623,6 +627,8 @@ void drm_sched_entity_set_priority(struct drm_sched_entity *entity,
enum drm_sched_priority priority);
bool drm_sched_entity_is_ready(struct drm_sched_entity *entity);
int drm_sched_entity_error(struct drm_sched_entity *entity);
+ktime_t drm_sched_entity_get_job_deadline(struct drm_sched_entity *entity,
+ struct drm_sched_job *job);
struct drm_sched_fence *drm_sched_fence_alloc(
struct drm_sched_entity *s_entity, void *owner);
Deadline scheduling policy should be a fairer flavour of FIFO with two main advantages being that it can naturally connect with the dma-fence deadlines, and secondly that it can get away with multiple run queues per scheduler. From the latter comes the fairness advantage. Where the current FIFO policy will always starve low priority entities by normal, and normal by high etc, deadline tracks all runnable entities in a single run queue and assigns them deadlines based on priority. Instead of being ordered strictly by priority, jobs and entities become ordered by deadlines. This means that a later higher priority submission can still overtake an earlier lower priority one, but eventually the lower priority will get its turn even if high priority is constantly feeding new work. Current mapping of priority to deadlines is somewhat arbitrary and looks like this (submit timestamp plus constant offset in micro-seconds): static const unsigned int d_us[] = { [DRM_SCHED_PRIORITY_KERNEL] = 100, [DRM_SCHED_PRIORITY_HIGH] = 1000, [DRM_SCHED_PRIORITY_NORMAL] = 5000, [DRM_SCHED_PRIORITY_LOW] = 100000, }; Assuming simultaneous submission of one normal and one low prioriy job at a time of "t", they will get respective deadlines of t+5ms and t+100ms. Hence normal will run first and low will run after it, or at the latest 100ms after it was submitted in case other higher priority submissions overtake it in the meantime. Because deadline policy does not need run queues, if the FIFO and RR polices are later removed, that would allow for a significant simplification of the code base by reducing the 1:N to 1:1 scheduler to run queue relationship. Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com> Cc: Christian König <christian.koenig@amd.com> Cc: Danilo Krummrich <dakr@redhat.com> Cc: Matthew Brost <matthew.brost@intel.com> Cc: Philipp Stanner <pstanner@redhat.com> --- drivers/gpu/drm/scheduler/sched_entity.c | 53 +++++++++++++++++++----- drivers/gpu/drm/scheduler/sched_main.c | 14 ++++--- drivers/gpu/drm/scheduler/sched_rq.c | 5 ++- include/drm/gpu_scheduler.h | 10 ++++- 4 files changed, 64 insertions(+), 18 deletions(-)