On Mon, Nov 16, 2015 at 09:54:10AM +0000, Tvrtko Ursulin wrote: > > Hi, > > On 15/11/15 13:32, Chris Wilson wrote: > >The busywait in __i915_spin_request() does not respect pending signals > >and so may consume the entire timeslice for the task instead of > >returning to userspace to handle the signal. > > Obviously correct to break the spin, but if spending a jiffie to > react to signals was the only problem then it is not too severe. > > Add something to the commit message about how it was found/reported > and about the severity of impact, etc? Perhaps: At the worst case this could cause a delay in signal processing of 20ms, which would be a noticeable jitter in cursor tracking. If a higher resolution signal was being used, for example to provide fairness of a server timeslices between clients, we could expect to detect some unfairness between clients. This issue was noticed when inspecting a report of poor interactivity resulting from excessively high __i915_spin_request usage. -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
