On Fri, Mar 20, 2015 at 10:59:50PM +0000, Chris Wilson wrote: > On Fri, Mar 20, 2015 at 04:19:02PM +0000, Chris Wilson wrote: > > I guess one test would be to see how many 1x1 [xN overdraw, say 1x1 > > Window, but rendering internally at 1080p] clients we can run in > > parallel whilst hitting 60fps. And then whether allowing multiple > > spinners helps or hinders. > > I was thinking of a nice easy test that could demonstrate any advantage > for spinning over waiting, and realised we already had such an igt. The > trick is that it has to generate sufficient GPU load to actually require > a wait, but not too high a GPU load such that we can see the impact from > slow completion. > > I present igt/gem_exec_blt (modified to repeat the measurement and do an > average over several runs): > > Time to blt 16384 bytes x 1: 21.000µs -> 5.800µs > Time to blt 16384 bytes x 2: 11.500µs -> 4.500µs > Time to blt 16384 bytes x 4: 6.750µs -> 3.750µs > Time to blt 16384 bytes x 8: 4.950µs -> 3.375µs > Time to blt 16384 bytes x 16: 3.825µs -> 3.175µs > Time to blt 16384 bytes x 32: 3.356µs -> 3.000µs > Time to blt 16384 bytes x 64: 3.259µs -> 2.909µs > Time to blt 16384 bytes x 128: 3.083µs -> 3.095µs > Time to blt 16384 bytes x 256: 3.104µs -> 2.979µs > Time to blt 16384 bytes x 512: 3.080µs -> 3.089µs > Time to blt 16384 bytes x 1024: 3.077µs -> 3.040µs > Time to blt 16384 bytes x 2048: 3.127µs -> 3.304µs > Time to blt 16384 bytes x 4096: 3.279µs -> 3.265µs We probably need to revisit this when the scheduler lands - that one will want to keep a short queue and generally will block for some request to complete. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
