Hello Pekka, Arthur, [...] > > > Would it be possible to have a standardised benchmark specifically > > > for performance rather than correctness, in IGT or where-ever it > > > would make sense? Then it would be simple to tell contributors to > > > run this and report the numbers before and after. > > > > > > I would propose this kind of KMS layout: > > > > > > - CRTC size 3841 x 2161 > > > - primary plane, XRGB8888, 3639 x 2161 @ 101,0 > > > - overlay A, XBGR2101010, 3033 x 1777 @ 201,199 > > > - overlay B, ARGB8888, 1507 x 1400 @ 1800,250 > > > > > > The sizes and positions are deliberately odd to try to avoid happy > > > alignment accidents. The planes are big, which should let the pixel > > > operations easily dominate performance measurement. There are > > > different pixel formats, both opaque and semi-transparent. There is > > > lots of plane overlap. The planes also do not cover the whole CRTC > > > leaving the background visible a bit. > > > > > > There should be two FBs per each plane, flipped alternatingly each > > > frame. Writeback should be active. Run this a number of frames, say, > > > 100, and measure the kernel CPU time taken. It's supposed to take at > > > least several seconds in total. > > > > > > I think something like this should be the base benchmark. One can > > > add more to it, like rotated planes, YUV planes, etc. or switch > > > settings on the existing planes. Maybe even FB_DAMAGE_CLIPS. Maybe > > > one more overlay that is very tall and thin. > > > > > > Just an idea, what do you all think? > > > > Hi Pekka, > > > > I just finished writing this proposal using IGT. > > > > I got pretty interesting results: > > > > The mentioned commit 8356b97906503a02125c8d03c9b88a61ea46a05a took > > around 13 seconds. While drm-misc/drm-misc-next took 36 seconds. > > > > I'm currently bisecting to be certain that the change to the > > pixel-by-pixel is the culprit, but I don't see why it wouldn't be. > > > > I just need to do some final touches on the benchmark code and it > > will be ready for revision. > > Awesome, thank you very much for doing that! > pq I also think it's a good benchmarks for classic configurations. The odd size is a very nice idea to verify the corner cases of line-by-line algorithms. When this is ready, please share the test, so I can check if my patch is as performant as before. Thank you for this work. Have a nice day, Louis Chauvet -- Louis Chauvet, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
