On 2021-08-24 10:46 a.m., Andrey Grodzovsky wrote:
On 2021-08-24 5:51 a.m., Monk Liu wrote:
the original logic is wrong that the timeout will not be retriggerd
after the previous job siganled, and that lead to the scenario that all
jobs in the same scheduler shares the same timeout timer from the very
begining job in this scheduler which is wrong.
we should modify the timer everytime a previous job signaled.
Signed-off-by: Monk Liu <Monk.Liu@xxxxxxx>
---
drivers/gpu/drm/scheduler/sched_main.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/drivers/gpu/drm/scheduler/sched_main.c
b/drivers/gpu/drm/scheduler/sched_main.c
index a2a9536..fb27025 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -235,6 +235,13 @@ static void drm_sched_start_timeout(struct
drm_gpu_scheduler *sched)
schedule_delayed_work(&sched->work_tdr, sched->timeout);
}
+static void drm_sched_restart_timeout(struct drm_gpu_scheduler
*sched)
+{
+ if (sched->timeout != MAX_SCHEDULE_TIMEOUT &&
+ !list_empty(&sched->pending_list))
+ mod_delayed_work(system_wq, &sched->work_tdr, sched->timeout);
3d point - if list empty you need to cancel the timer, let the new job
coming after that restart it.
Andrey
+}
+
/**
* drm_sched_fault - immediately start timeout handler
*
@@ -693,6 +700,11 @@ drm_sched_get_cleanup_job(struct
drm_gpu_scheduler *sched)
if (job && dma_fence_is_signaled(&job->s_fence->finished)) {
/* remove job from pending_list */
list_del_init(&job->list);
+
+ /* once the job deleted from pending list we should restart
+ * the timeout calculation for the next job.
+ */
+ drm_sched_restart_timeout(sched);
I think this should work, but 2 points -
1st you should probably remove this now
https://elixir.bootlin.com/linux/v5.14-rc1/source/drivers/gpu/drm/scheduler/sched_main.c#L797
2nd - if you have two adjacent jobs started very closely you
effectively letting the second job to be twice longer hang without TDR
because
you reset TDR timer for it when it's almost expired. If we could have
TTL (time to live counter) for each job and then do mod_delayed_work
to the TTL of the following job instead of just full timer reset then
this would be more precise. But this is more of recommendation for
improvement.
Andrey
/* make the scheduled timestamp more accurate */
next = list_first_entry_or_null(&sched->pending_list,
typeof(*next), list);