From a2dd2ff50cde3cbbeecec72225bb18582b291f14 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Wed, 20 Jan 2021 12:17:18 +0000 Subject: [PATCH] drm/i915/gt: Skip over completed active execlists, again Now that we are careful to always force-restore contexts upon rewinding (where necessary), we can restore our optimisation to skip over completed active execlists when dequeuing. Referenecs: 35f3fd8182ba ("drm/i915/execlists: Workaround switching back to a completed context") References: 8ab3a3812aa9 ("drm/i915/gt: Incrementally check for rewinding") Signed-off-by: Chris Wilson Cc: Mika Kuoppala Reviewed-by: Mika Kuoppala Link: https://patchwork.freedesktop.org/patch/msgid/20210120121718.26435-2-chris@chris-wilson.co.uk --- .../gpu/drm/i915/gt/intel_execlists_submission.c | 34 ++++++++++------------ 1 file changed, 16 insertions(+), 18 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c index 524c8b5..ac1be7a 100644 --- a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c +++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c @@ -1224,12 +1224,20 @@ static void set_preempt_timeout(struct intel_engine_cs *engine, active_preempt_timeout(engine, rq)); } +static bool completed(const struct i915_request *rq) +{ + if (i915_request_has_sentinel(rq)) + return false; + + return __i915_request_is_complete(rq); +} + static void execlists_dequeue(struct intel_engine_cs *engine) { struct intel_engine_execlists * const execlists = &engine->execlists; struct i915_request **port = execlists->pending; struct i915_request ** const last_port = port + execlists->port_mask; - struct i915_request *last = *execlists->active; + struct i915_request *last, * const *active; struct virtual_engine *ve; struct rb_node *rb; bool submit = false; @@ -1266,21 +1274,13 @@ static void execlists_dequeue(struct intel_engine_cs *engine) * i.e. we will retrigger preemption following the ack in case * of trouble. * - * In theory we can skip over completed contexts that have not - * yet been processed by events (as those events are in flight): - * - * while ((last = *active) && i915_request_completed(last)) - * active++; - * - * However, the GPU cannot handle this as it will ultimately - * find itself trying to jump back into a context it has just - * completed and barf. */ + active = execlists->active; + while ((last = *active) && completed(last)) + active++; if (last) { - if (__i915_request_is_complete(last)) { - goto check_secondary; - } else if (need_preempt(engine, last)) { + if (need_preempt(engine, last)) { ENGINE_TRACE(engine, "preempting last=%llx:%lld, prio=%d, hint=%d\n", last->fence.context, @@ -1359,9 +1359,7 @@ 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)) { + if (active[1]) { /* * Even if ELSP[1] is occupied and not worthy * of timeslices, our queue might be. @@ -1562,7 +1560,7 @@ done: * of ordered contexts. */ if (submit && - memcmp(execlists->active, + memcmp(active, execlists->pending, (port - execlists->pending) * sizeof(*port))) { *port = NULL; @@ -1570,7 +1568,7 @@ done: execlists_schedule_in(*port, port - execlists->pending); WRITE_ONCE(execlists->yield, -1); - set_preempt_timeout(engine, *execlists->active); + set_preempt_timeout(engine, *active); execlists_submit_ports(engine); } else { ring_set_paused(engine, 0); -- 2.7.4