Quoting Tvrtko Ursulin (2017-11-24 07:32:30) > > On 23/11/17 16:07, Chris Wilson wrote: > > Quoting Chris Wilson (2017-11-23 16:02:20) > >> Quoting Tvrtko Ursulin (2017-11-23 13:37:30) > >>> > >>> On 23/11/2017 08:22, Chris Wilson wrote: > >>>> Make sure the HW is idle before we start sampling the GPU for busyness. > >>>> If we do not rest for long enough between tests, we may carry the > >>>> sampling over. > >>> > >>> I'd rather not have this since as I said yesterday each opened PMU event > >>> is supposed to record the initial counter value as reference. If that is > >>> failing or not good enough on some tests/platforms I would rather first > >>> understand why and how. > >> > >> All legacy sampling fails... :| I'm putting it back! > > > > So presumably it is coupling with the parking. > > Or more precisely averaging with the previous sample. Every time one PMU > client signals the timer to self-disarm, but the new PMU client enables > the timer again in this window, the previous sample value does not get > cleared. [snip] > But it is too evil to wait for the sampling timer in case of MMIO in the > irq disabled section. Even though it would happen only on disable-enable > transitions quicker than sampling period. It is not an use case, but still.. > > Or we could drop sample averaging.. ? Yeah, we are accumulating too much cruft for a small improvement (that only affects the endpoints). -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
