Quoting Michał Winiarski (2017-10-26 11:52:31) > On Thu, Oct 26, 2017 at 08:31:27AM +0100, Chris Wilson wrote: > > For measuring the cost of preemption, inject a low priority spinner > > between the two measurements; the difference between the preemption and > > the normal dispatch includes both the cost of the spinner dispatch and > > of preempting it. Close enough for us to estimate the cost of > > preemption, though we don't measure the cost of preemption on the local > > ring! > > And as expected, we're seeing more delay with GuC, probably from worker > scheduling delay (~2ms on my SKL if I'm reading the results correctly). Don't look at bxt then ;) Another order or magnitude. Most of that can be ascribed to using a worker, so we should be able to pare it back somewhat. Just the idea that the GuC may take 10ms to respond to a request is a bit disconcerting! Do we have to wait for the ack from the preempt request? Could we farm that off to some other poor task? Then we would be in a position to avoid that mutex and process-context worker. Oh well, you probably already have ideas and plans for replacing that mutex :) -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
