On 24/11/2020 17:38, Chris Wilson wrote:
Quoting Tvrtko Ursulin (2020-11-24 17:19:23)
On 24/11/2020 11:42, Chris Wilson wrote:
Pull the repeated check for the last active request being completed to a
single spot, when deciding whether or not execlist preemption is
required.
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/gt/intel_lrc.c | 15 ++++-----------
1 file changed, 4 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index cf11cbac241b..43703efb36d1 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -2141,12 +2141,9 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
*/
if ((last = *active)) {
- if (need_preempt(engine, last, rb)) {
- if (i915_request_completed(last)) {
- tasklet_hi_schedule(&execlists->tasklet);
- return;
- }
-
+ if (i915_request_completed(last)) {
+ goto check_secondary;
+ } else if (need_preempt(engine, last, rb)) {
ENGINE_TRACE(engine,
"preempting last=%llx:%lld, prio=%d, hint=%d\n",
last->fence.context,
@@ -2174,11 +2171,6 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
last = NULL;
} else if (need_timeslice(engine, last, rb) &&
timeslice_expired(execlists, last)) {
- if (i915_request_completed(last)) {
- tasklet_hi_schedule(&execlists->tasklet);
- return;
- }
-
ENGINE_TRACE(engine,
"expired last=%llx:%lld, prio=%d, hint=%d, yield?=%s\n",
last->fence.context,
@@ -2214,6 +2206,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
* we hopefully coalesce several updates into a single
* submission.
*/
+check_secondary:
if (!list_is_last(&last->sched.link,
&engine->active.requests)) {
Is there a tasklet_hi_schedule in here? I see set_timeslice in my checkout.
That tasklet_hi_schedule() was a mistake. It just devolves into a
busy-spinner as we wait for HW to send the next event, which turns out
not to be as instantaneous as hoped.
I recall leaving the imprint of my palm on my face when I figured out
what was causing the spike in the profile.
Okay, if you mention that in the commit message you can add my rb.
Regards,
Tvrtko
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