[FFmpeg-devel] swscale/rgb2rgb : add X86_64 SIMD (SSSE3 and AVX2) for shuffly_bytes func

[Paul B Mahol]

On 3/18/18, Nicolas George <george at 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.