Chris Wilson <[email protected]> writes: > If we change the priority of the active context, then it has no impact > on the decision of whether to preempt the active context -- we don't > preempt the context with itself. In this situation, we elide the tasklet > rescheduling and should *not* be marking up the queue_priority_hint as > that may mask a later submission where we decide we don't have to kick > the tasklet as a higher priority submission is pending (spoiler alert, > it was not). > > Signed-off-by: Chris Wilson <[email protected]> > Cc: Tvrtko Ursulin <[email protected]> > Cc: Mika Kuoppala <[email protected]> > --- > drivers/gpu/drm/i915/i915_scheduler.c | 37 ++++++++++++++++----------- > 1 file changed, 22 insertions(+), 15 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_scheduler.c > b/drivers/gpu/drm/i915/i915_scheduler.c > index 0ca40f6bf08c..d2edb527dcb8 100644 > --- a/drivers/gpu/drm/i915/i915_scheduler.c > +++ b/drivers/gpu/drm/i915/i915_scheduler.c > @@ -189,22 +189,34 @@ static inline bool need_preempt(int prio, int active) > return prio >= max(I915_PRIORITY_NORMAL, active); > } > > -static void kick_submission(struct intel_engine_cs *engine, int prio) > +static void kick_submission(struct intel_engine_cs *engine, > + const struct i915_request *rq, > + int prio) > { > - const struct i915_request *inflight = > - execlists_active(&engine->execlists); > + const struct i915_request *inflight; > + > + /* > + * We only need to kick the tasklet once for the high priority > + * new context we add into the queue. > + */ > + if (prio <= engine->execlists.queue_priority_hint) > + return; > + > + /* Nothing currently active? We're overdue for a submission! */ > + inflight = execlists_active(&engine->execlists); > + if (!inflight) > + return; > > /* > * If we are already the currently executing context, don't > - * bother evaluating if we should preempt ourselves, or if > - * we expect nothing to change as a result of running the > - * tasklet, i.e. we have not change the priority queue > - * sufficiently to oust the running context. > + * bother evaluating if we should preempt ourselves. > */ > - if (!inflight || !need_preempt(prio, rq_prio(inflight))) > + if (inflight->hw_context == rq->hw_context)
If there is a tail update at this moment, does the hardware take it into account or do we need to kick? -Mika > return; > > - tasklet_hi_schedule(&engine->execlists.tasklet); > + engine->execlists.queue_priority_hint = prio; > + if (need_preempt(prio, rq_prio(inflight))) > + tasklet_hi_schedule(&engine->execlists.tasklet); > } > > static void __i915_schedule(struct i915_sched_node *node, > @@ -330,13 +342,8 @@ static void __i915_schedule(struct i915_sched_node *node, > list_move_tail(&node->link, cache.priolist); > } > > - if (prio <= engine->execlists.queue_priority_hint) > - continue; > - > - engine->execlists.queue_priority_hint = prio; > - > /* Defer (tasklet) submission until after all of our updates. */ > - kick_submission(engine, prio); > + kick_submission(engine, node_to_request(node), prio); > } > > spin_unlock(&engine->active.lock); > -- > 2.24.0.rc0 _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
