On 03/10/2019 22:00, Chris Wilson wrote:
If we unwind the active requests, and on resubmission discover that we
intend to preempt the active context with itself, simply skip the ELSP
submission.
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/gt/intel_lrc.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 431d3b8c3371..3cfea1758fd2 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -1739,11 +1739,26 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
if (submit) {
*port = execlists_schedule_in(last, port - execlists->pending);
- memset(port + 1, 0, (last_port - port) * sizeof(*port));
execlists->switch_priority_hint =
switch_prio(engine, *execlists->pending);
+
+ /*
+ * Skip if we ended up with exactly the same set of requests,
+ * e.g. trying to timeslice a pair of ordered contexts
+ */
+ if (!memcmp(execlists->active, execlists->pending,
+ (port - execlists->pending + 1) * sizeof(*port))) {
+ do
+ execlists_schedule_out(fetch_and_zero(port));
+ while (port-- != execlists->pending);
+
+ goto skip_submit;
+ }
+
+ memset(port + 1, 0, (last_port - port) * sizeof(*port));
execlists_submit_ports(engine);
} else {
+skip_submit:
ring_set_paused(engine, 0);
}
}
A little bit of tracepoint noise with in/out but looks correct after I
read the new code. And I wonder if trace.pl still works after last
couple months of refactors.. :)
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Regards,
Tvrtko
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