On Thu, Mar 22, 2018 at 09:28:00AM +0000, Chris Wilson wrote: > Quoting Tvrtko Ursulin (2018-03-22 09:22:55) > > > > On 21/03/2018 17:26, jeff.mcgee@xxxxxxxxx wrote: > > > From: Jeff McGee <jeff.mcgee@xxxxxxxxx> > > > > > > Force preemption uses engine reset to enforce a limit on the time > > > that a request targeted for preemption can block. This feature is > > > a requirement in automotive systems where the GPU may be shared by > > > clients of critically high priority and clients of low priority that > > > may not have been curated to be preemption friendly. There may be > > > more general applications of this feature. I'm sharing as an RFC to > > > stimulate that discussion and also to get any technical feedback > > > that I can before submitting to the product kernel that needs this. > > > I have developed the patches for ease of rebase, given that this is > > > for the moment considered a non-upstreamable feature. It would be > > > possible to refactor hangcheck to fully incorporate force preemption > > > as another tier of patience (or impatience) with the running request. > > > > Sorry if it was mentioned elsewhere and I missed it - but does this work > > only with stateless clients - or in other words, what would happen to > > stateful clients which would be force preempted? Or the answer is we > > don't care since they are misbehaving? > > They get notified of being guilty for causing a gpu reset; three strikes > and they are out (banned from using the gpu) using the current rules. > This is a very blunt hammer that requires the rest of the system to be > robust; one might argue time spent making the system robust would be > better served making sure that the timer never expired in the first place > thereby eliminating the need for a forced gpu reset. > -Chris Yes, for simplication the policy applied to force preempted contexts is the same as for hanging contexts. It is known that this feature should not be required in a fully curated system. It's a requirement if end user will be alllowed to install 3rd party apps to run in the non-critical domain. -Jeff _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
