Quoting Chris Wilson (2020-05-06 15:36:16) > Make sure we ignore the I915_PRIORITY_WAIT hint when looking at > timeslicing, as we do not treat it as a preemption request but as a soft > ordering hint. If we apply the hint, then when we recompute the ordering > after unwinding for the timeslice, we will often leave the order > unchanged due to the soft-hint. However, if we apply it to all those we > unwind, then the two equivalent levels may be reordered, and since the > dependencies will be replayed in order, we will not change the order of > dependencies. > > There is a small issue with the lack of cross-engine priority bumping on > unwind, leaving the total graph slightly unordered; but that will not > result in any misordering of rendering on remote machines as any > signalers will also be live. Though there may be a danger that this will > upset our sanitychecks. > > Why keep the I915_PRIORITY_WAIT soft-hint, I hear Tvrtko ask? Despite > the many hairy tricks we play to have the hint and then ignore it, I > still like the concept of codel and the promise that it gives for low > latency of independent queues! Tvrtko is warned not to ask when we replace strict priorities with isoschronous and psuedo-deadline scheduling. -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
