On Tue, Aug 18, 2020 at 01:11:30PM -0500, Sebastian Pop wrote: > Hi, > > Unrolling by 4 the outer loop in yuv2planeX reduces the number of cache > accesses by 7.5%. > The values loaded for the filter are used in the 4 unrolled iterations and > avoids reloading 3 times the same values. > The performance was measured on an Arm64 Neoverse-N1 Graviton2 c6g.metal > instance with the following command: > $ perf stat -e cache-references ./ffmpeg_g -nostats -f lavfi -i > testsrc2=4k:d=2 -vf bench=start,scale=1024x1024,bench=stop -f null - > > before: 1551591469 cache-references > after: 1436140431 cache-references > > before: [bench @ 0xaaaac62b7d30] t:0.013226 avg:0.013219 max:0.013537 > min:0.012975 > after: [bench @ 0xaaaad84f3d30] t:0.012355 avg:0.012381 max:0.013164 > min:0.012158 >
> Ok to commit? faster is better obviously, so if its tested with odd sizes and arm developers had a chance to comment. it should be ok one potential improvment is to use the unrolled code for odd width too and use the non unrolled for the end thx [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Many things microsoft did are stupid, but not doing something just because microsoft did it is even more stupid. If everything ms did were stupid they would be bankrupt already.
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