On Thu, Mar 12, 2015 at 01:14:30PM +0000, Tvrtko Ursulin wrote: > On 03/12/2015 11:11 AM, Chris Wilson wrote: > >This provides a nice boost to mesa in swap bound scenarios (as mesa > >throttles itself to the previous frame and given the scenario that will > >complete shortly). It will also provide a good boost to systems running > >with semaphores disabled and so frequently waiting on the GPU as it > >switches rings. In the most favourable of microbenchmarks, this can > >increase performance by around 15% - though in practice improvements > >will be marginal and rarely noticeable. > > > >v2: Account for user timeouts > >v3: Limit the spinning to a single jiffie (~1us) at most. On an > >otherwise idle system, there is no scheduler contention and so without a > >limit we would spin until the GPU is ready. > > Isn't one jiffie 1-10ms typically? 1ms. I was just thinking of doing USECS_PER_SEC / HZ, then realised that was a jiffie, hence the confusion. At any rate, it is still the minimum we can trivially wait for (without an expensive hrtimer). -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
