[PATCH 1/2] drm/scheduler: Add job dependency trace.

[Andrey Grodzovsky <andrey.grodzovsky@xxxxxxx>]

During debug sessions I encountered a need to trace
back a job dependecy a few steps back to the first failing
job. This trace helpped me a lot.

Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@xxxxxxx>
---
 drivers/gpu/drm/scheduler/gpu_scheduler.c       |  8 ++++++--
 drivers/gpu/drm/scheduler/gpu_scheduler_trace.h | 24 ++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/scheduler/gpu_scheduler.c b/drivers/gpu/drm/scheduler/gpu_scheduler.c
index 3f2fc5e..45703b9 100644
--- a/drivers/gpu/drm/scheduler/gpu_scheduler.c
+++ b/drivers/gpu/drm/scheduler/gpu_scheduler.c
@@ -506,9 +506,13 @@ drm_sched_entity_pop_job(struct drm_sched_entity *entity)
 	if (!sched_job)
 		return NULL;
 
-	while ((entity->dependency = sched->ops->dependency(sched_job, entity)))
-		if (drm_sched_entity_add_dependency_cb(entity))
+	while ((entity->dependency = sched->ops->dependency(sched_job, entity))) {
+		if (drm_sched_entity_add_dependency_cb(entity)) {
+
+			trace_drm_sched_job_wait_dep(sched_job, entity->dependency);
 			return NULL;
+		}
+	}
 
 	/* skip jobs from entity that marked guilty */
 	if (entity->guilty && atomic_read(entity->guilty))
diff --git a/drivers/gpu/drm/scheduler/gpu_scheduler_trace.h b/drivers/gpu/drm/scheduler/gpu_scheduler_trace.h
index 4998ad9..1626f39 100644
--- a/drivers/gpu/drm/scheduler/gpu_scheduler_trace.h
+++ b/drivers/gpu/drm/scheduler/gpu_scheduler_trace.h
@@ -74,6 +74,30 @@ TRACE_EVENT(drm_sched_process_job,
 	    TP_printk("fence=%p signaled", __entry->fence)
 );
 
+TRACE_EVENT(drm_sched_job_wait_dep,
+	    TP_PROTO(struct drm_sched_job *sched_job, struct dma_fence *fence),
+	    TP_ARGS(sched_job, fence),
+	    TP_STRUCT__entry(
+			     __field(const char *,name)
+			     __field(uint64_t, id)
+			     __field(struct dma_fence *, fence)
+			     __field(uint64_t, ctx)
+			     __field(unsigned, seqno)
+			     ),
+
+	    TP_fast_assign(
+			   __entry->name = sched_job->sched->name;
+			   __entry->id = sched_job->id;
+			   __entry->fence = fence;
+			   __entry->ctx = fence->context;
+			   __entry->seqno = fence->seqno;
+			   ),
+	    TP_printk("job ring=%s, id=%llu, depends fence=%p, context=%llu, seq=%u",
+		      __entry->name, __entry->id,
+		      __entry->fence, __entry->ctx,
+		      __entry->seqno)
+);
+
 #endif
 
 /* This part must be outside protection */
-- 
2.7.4

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