[Intel-gfx] [PATCH] drm/i915/guc: Disable preemption if it fails

[Singh, Satyeshwar]

Hi Chris,
Isn't this dependent upon the workload submitted to the GuC? Meaning we have one workload that refused to be preempted (really long shader for example) but it went away on its own. Other workloads that come in later are preemptible. However, if we turn off preemption permanently, then all future workloads will not be preempted either which may not be desirable.
-Satyeshwar

-----Original Message-----
From: Intel-gfx [mailto:intel-gfx-bounces at lists.freedesktop.org] On Behalf Of Chris Wilson
Sent: Thursday, May 31, 2018 1:47 PM
To: intel-gfx at lists.freedesktop.org
Subject: [Intel-gfx] [PATCH] drm/i915/guc: Disable preemption if it fails

If we fail to tell the GuC to perform preemption, we get stuck attempting to continually retry inject_preempt_context() until we eventually timeout and reset the GPU (approximately emitting the same warning 1000 times). Bail after the first failure, emit the WARN and stop trying to do any further preemption on this engine.

References: https://intel-gfx-ci.01.org/tree/drm-tip/Trybot_2235/shard-apl4/igt@gem_exec_schedule@preempt-bsd.html
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Michal Wajdeczko <michal.wajdeczko at intel.com>
Cc: Michel Thierry <michel.thierry at intel.com>
Cc: Michałt Winiarski <michal.winiarski at intel.com>
---
 drivers/gpu/drm/i915/intel_guc_submission.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/i915/intel_guc_submission.c b/drivers/gpu/drm/i915/intel_guc_submission.c
index 133367a17863..24bdac205c45 100644
--- a/drivers/gpu/drm/i915/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/intel_guc_submission.c
@@ -588,6 +588,7 @@ static void inject_preempt_context(struct work_struct *work)
 	data[6] = intel_guc_ggtt_offset(guc, guc->shared_data);
 
 	if (WARN_ON(intel_guc_send(guc, data, ARRAY_SIZE(data)))) {
+		engine->flags &= ~I915_ENGINE_HAS_PREEMPTION; /* XXX racy! */
 		execlists_clear_active(&engine->execlists,
 				       EXECLISTS_ACTIVE_PREEMPT);
 		tasklet_schedule(&engine->execlists.tasklet);
--
2.17.1

_______________________________________________
Intel-gfx mailing list
Intel-gfx at lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx