@@ -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)) {
/*
Pull the repeated check for the last active request being completed to a single spot, when deciding whether or not execlist preemption is required. In doing so, we remove the tasklet kick, introduced with the completion checks in commit 35f3fd8182ba ("drm/i915/execlists: Workaround switching back to a completed context"), if we find the request was completed but have not yet seen the corresponding CS event. This was devolving into a busy spin of the tasklet while we waited for the event as the delivery was not as instantaneous as expected. Under load this is sufficient to exhaust the tasklet softirq timeslice, and force ksoftirqd. Quite noticeable overhead for no apparent improvement in latency. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> --- drivers/gpu/drm/i915/gt/intel_lrc.c | 15 ++++----------- 1 file changed, 4 insertions(+), 11 deletions(-)