Quoting Tvrtko Ursulin (2019-11-19 15:04:46) > > On 18/11/2019 23:02, Chris Wilson wrote: > > diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c > > index 33ce258d484f..f7c8fec436a9 100644 > > --- a/drivers/gpu/drm/i915/gt/intel_lrc.c > > +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c > > @@ -142,6 +142,7 @@ > > #include "intel_engine_pm.h" > > #include "intel_gt.h" > > #include "intel_gt_pm.h" > > +#include "intel_gt_requests.h" > > #include "intel_lrc_reg.h" > > #include "intel_mocs.h" > > #include "intel_reset.h" > > @@ -2278,6 +2279,18 @@ static void execlists_submission_tasklet(unsigned long data) > > if (timeout && preempt_timeout(engine)) > > preempt_reset(engine); > > } > > + > > + /* > > + * If the GPU is currently idle, retire the outstanding completed > > + * requests. This will allow us to enter soft-rc6 as soon as possible, > > + * albeit at the cost of running the retire worker much more frequently > > + * (over the entire GT not just this engine) and emitting more idle > > + * barriers (i.e. kernel context switches unpinning all that went > > + * before) which may add some extra latency. > > + */ > > + if (intel_engine_pm_is_awake(engine) && > > + !execlists_active(&engine->execlists)) > > + intel_gt_schedule_retire_requests(engine->gt); > > I am still not a fan of doing this for all platforms. I understand. I think it makes a fair amount of sense to do early retires, and wish to pursue that if I can show there is no harm. > Its not just the cost of retirement but there is > intel_engine_flush_submission on all engines in there as well which we > cannot avoid triggering from this path. > > Would it be worth experimenting with additional per-engine retire > workers? Most of the code could be shared, just a little bit of > specialization to filter on engine. I haven't sketched out anything more than peeking at the last request on the timeline and doing a rq->engine == engine filter. Walking the global timeline.active_list in that case is also a nuisance. There's definitely scope here for us using some more information from process_csb() about which context completed and limit work to that timeline. Hmm, something along those lines maybe... -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
