On 2016-12-02 00:31, Carl Eugen Hoyos wrote: > 2016-12-01 17:57 GMT+01:00 James Darnley <jdarn...@obe.tv>: >> Yorkfield: >> - mmx2: 2.44x faster (278 vs. 114 cycles) >> - sse2: 3.35x faster (278 vs. 83 cycles) >> >> Skylake: >> - mmx2: 1.69x faster (169 vs. 100 cycles) >> - sse2: 2.34x faster (169 vs. 72 cycles) > > Is it expected (or possible) that the speed impact is so > different for different Intel hardware?
Yes. Intel's Core branded processors introduced a much better micro-architecture (the generation after the Yorkfield) which will cause the scalar C code to be quite a bit faster. The SIMD on the other hand was already so quick it didn't gain much. (At least I think I remember this being the story.) >> - avx: 2.32x faster (169 vs. 73 cycles) > > Don't you agree that if this is true (I don't know if it is) > the patch should not be applied as is? I do agree and I wouldn't (deliberately) apply anything that made the decoder slower, or not as fast as it could be. _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
