Quoting Tvrtko Ursulin (2017-11-24 09:49:59) > From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> > > Averaging with the previous sample brings a small statistical improvement > to sampling counters, but can leek a little bit of state from a current > client to the next which mulls the border between past and present for > observing clients. > > This is because on event enable clients record the current counter value > and use it as reference, but with rapid off-on event cycles, and due the > delayed nature of sampling timer self-disarm, previous sample value does > not get cleared under these circumstances. > > Solution is to stop averaging with the previous sample. This has a small > downside of losing some precision with short and spiky signals, but the > alternatives look too complicated for the benefit. > > Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> > Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > Cc: Sagar Arun Kamble <sagar.a.kamble@xxxxxxxxx> Nothing wrong with the patch, and I agree that chasing that little bit of smoothness is not worth the complexity in the edge cases. Oh well. Reviewed-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> (Until such a time as we have a clean way of being perfect, good enough.) -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
