On Thu, Jan 15, 2015 at 05:05:30PM +0000, Tvrtko Ursulin wrote: > > On 01/15/2015 04:54 PM, Ben Widawsky wrote: > >On Thu, Jan 15, 2015 at 11:21:30AM +0000, Tvrtko Ursulin wrote: > >>From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> > >> > >>This eliminates six needless spin lock/unlock pairs when writing out ELSP. Apart > >>from tidier code main benefit is between 0.51% and 0.73% speedup on some OGL > >>tests under CHV (bench_OglBatch4 bench_OglDeferred respectively). > > > >With 95% confidence t-test on n=5 > > > >> > >>Kindly benchmarked by Ben Widawsky. > > > >FWIW, as I mentioned on IRC, I think the reduction of the unnecessary forcewake > >(someone should fix the shadow register list) is probably more beneficial than > >removing the spin on an uncontested lock. I was tempted to try that myself, but > >I didn't have time or much interest since your patch accomplishes the same > >thing. > > I missed that IRC discussion, but I don't think it was doing forcewakes > since the outer block in execlists_elsp_write bumps the counters which made > I915_WRITE & co skip them. > > Regards, > > Tvrtko I didn't check the locking but it looks like it could actually get decremented once the spinlock is released. Probably never happens, but I think it's possible. I completely missed that block somehow. I think my eyes skipped over it because how could getting forcewake take like 10+ lines :D _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
