Quoting Tvrtko Ursulin (2018-06-05 15:02:53) > From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> > > As Chris has discovered on his Ivybridge, and later automated test runs > have confirmed, on most of our platforms hrtimer faced with heavy GPU load > can occasionally become sufficiently imprecise to affect PMU sampling > calculations. > > This means we cannot assume sampling frequency is what we asked for, but > we need to measure the interval ourselves. > > This patch is similar to Chris' original proposal for per-engine counters, > but instead of introducing a new set to work around the problem with > frequency sampling, it swaps around the way internal frequency accounting > is done. Instead of accumulating current frequency and dividing by > sampling frequency on readout, it accumulates frequency scaled by each > period. > > v2: > * Typo in commit message, comment on period calculation and USER_PER_SEC. > (Chris Wilson) Ironic typo in pointing out the typo? /me can't tell if it's humour or just an annoying user. -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
