2018-03-18 17:46 GMT+01:00, Martin Vignali <martin.vign...@gmail.com>: > 2018-03-18 17:37 GMT+01:00 Paul B Mahol <one...@gmail.com>: > >> On 3/18/18, Nicolas George <geo...@nsup.org> wrote: >> > Martin Vignali (2018-03-18): >> >> I run the test again with a bigger width (512 instead of 128) >> >> This is my result : >> >> shuffle_bytes_0321_c: 128.6 >> >> shuffle_bytes_0321_ssse3: 41.6 >> >> shuffle_bytes_0321_avx2: 23.4 >> > >> > IIUC, these benchmarks are expressed in CPU cycles. But what James says >> > is that it can cause the CPU frequency to be throttled: if that happens, >> > less cycles can use more time, and even worse, cause other unrelated to >> > take more time. A benchmark in actual time and typical use case would be >> > needed to decide. >> >> Yes, always also test overall with typical code usecase.
+1 > I tested it using a "benchmark" command line, who test two shuffle func > ./ffmpeg -benchmark -f lavfi -i rgbtestsrc=size=3840x2160:duration=10 -vf > format=argb,format=rgba -f null - > > With the patch : > bench: utime=3.611s > With only SSSE 3 (disable AVX2 part), i have similar result. Indicating James' original comment that the avx2 optimization makes no sense is correct? Carl Eugen _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
