diff options
| author | Matthew Brost <matthew.brost@intel.com> | 2023-10-30 20:24:36 -0700 |
|---|---|---|
| committer | Luben Tuikov <ltuikov89@gmail.com> | 2023-11-01 17:29:21 -0400 |
| commit | a6149f0393699308fb00149be913044977bceb56 (patch) | |
| tree | 893c8d5e70a5d877e7bf9a787e7b07702a8ef121 /drivers/gpu/drm/nouveau/nouveau_sched.c | |
| parent | 35963cf2cd25eeea8bdb4d02853dac1e66fb13a0 (diff) | |
drm/sched: Convert drm scheduler to use a work queue rather than kthread
In Xe, the new Intel GPU driver, a choice has made to have a 1 to 1
mapping between a drm_gpu_scheduler and drm_sched_entity. At first this
seems a bit odd but let us explain the reasoning below.
1. In Xe the submission order from multiple drm_sched_entity is not
guaranteed to be the same completion even if targeting the same hardware
engine. This is because in Xe we have a firmware scheduler, the GuC,
which allowed to reorder, timeslice, and preempt submissions. If a using
shared drm_gpu_scheduler across multiple drm_sched_entity, the TDR falls
apart as the TDR expects submission order == completion order. Using a
dedicated drm_gpu_scheduler per drm_sched_entity solve this problem.
2. In Xe submissions are done via programming a ring buffer (circular
buffer), a drm_gpu_scheduler provides a limit on number of jobs, if the
limit of number jobs is set to RING_SIZE / MAX_SIZE_PER_JOB we get flow
control on the ring for free.
A problem with this design is currently a drm_gpu_scheduler uses a
kthread for submission / job cleanup. This doesn't scale if a large
number of drm_gpu_scheduler are used. To work around the scaling issue,
use a worker rather than kthread for submission / job cleanup.
v2:
- (Rob Clark) Fix msm build
- Pass in run work queue
v3:
- (Boris) don't have loop in worker
v4:
- (Tvrtko) break out submit ready, stop, start helpers into own patch
v5:
- (Boris) default to ordered work queue
v6:
- (Luben / checkpatch) fix alignment in msm_ringbuffer.c
- (Luben) s/drm_sched_submit_queue/drm_sched_wqueue_enqueue
- (Luben) Update comment for drm_sched_wqueue_enqueue
- (Luben) Positive check for submit_wq in drm_sched_init
- (Luben) s/alloc_submit_wq/own_submit_wq
v7:
- (Luben) s/drm_sched_wqueue_enqueue/drm_sched_run_job_queue
v8:
- (Luben) Adjust var names / comments
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Luben Tuikov <luben.tuikov@amd.com>
Link: https://lore.kernel.org/r/20231031032439.1558703-3-matthew.brost@intel.com
Signed-off-by: Luben Tuikov <ltuikov89@gmail.com>
Diffstat (limited to 'drivers/gpu/drm/nouveau/nouveau_sched.c')
| -rw-r--r-- | drivers/gpu/drm/nouveau/nouveau_sched.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/gpu/drm/nouveau/nouveau_sched.c b/drivers/gpu/drm/nouveau/nouveau_sched.c index e62b04109b2f..7e64b5ef90fb 100644 --- a/drivers/gpu/drm/nouveau/nouveau_sched.c +++ b/drivers/gpu/drm/nouveau/nouveau_sched.c @@ -429,7 +429,7 @@ int nouveau_sched_init(struct nouveau_drm *drm) if (!drm->sched_wq) return -ENOMEM; - return drm_sched_init(sched, &nouveau_sched_ops, + return drm_sched_init(sched, &nouveau_sched_ops, NULL, DRM_SCHED_PRIORITY_COUNT, NOUVEAU_SCHED_HW_SUBMISSIONS, 0, job_hang_limit, NULL, NULL, "nouveau_sched", drm->dev->dev); |