Quoting Chris Wilson (2019-03-01 10:22:30) > Quoting Tvrtko Ursulin (2019-02-28 13:20:50) > > > > On 26/02/2019 10:24, Chris Wilson wrote: > > > If we resubmitting the active context, simply skip the submission as > > > > we are > > It took multiple reads to even notice that the third word was missing, > mainly because I kept skipping the "we". > > > > performing the submission from the interrupt handler has higher > > > > From the tasklet? > > Yes, the interrupt handler bottom half. > > > You mean wait for ctx complete and then > > execlists_dequeue, instead of lite-restore? > > Yes. We can measure the relatively large impact of lite-restoring on > throughput (the delay in the GPU reloading the context is quite > noticeable), but it only affects a certain microbenchmark. In theory, > making sure we avoid the stall while handling the interrupt and > resubmitting should offset that cost and be much preferred for > multi-context situations, but there the interrupt overhead on an *idle* > system (~5-7us) is not as significant and so the impact seems not as > significant (in fact due to quirky hw, sometimes it is preferable not to > resubmit during an inflight CS event). On idle systems, that lite-restore cost is visible even on top of a normal context switch, i.e. submitting A, AB, [CS interrupt], B is marginally slower than A, [CS interrupt], B !!! /o\ Sometimes I don't get our HW at all, -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
