[FFmpeg-devel] [FFmpeg-cvslog] avutil/mem: Optimize fill32() by unrolling and using 64bit

[Carl Eugen Hoyos]

2019-01-20 22:22 GMT+01:00, Michael Niedermayer <git at videolan.org>:
> ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Thu
> Jan 17 22:35:10 2019 +0100| [12b1338be376a3e5fb606d9fe41b58dc4a9e62c7] |
> committer: Michael Niedermayer
>
> avutil/mem: Optimize fill32() by unrolling and using 64bit
>
> Reviewed-by: Marton Balint <cus at passwd.hu>
> Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
>
>> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=12b1338be376a3e5fb606d9fe41b58dc4a9e62c7
> ---
>
>  libavutil/mem.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
>
> diff --git a/libavutil/mem.c b/libavutil/mem.c
> index 6149755a6b..88fe09b179 100644
> --- a/libavutil/mem.c
> +++ b/libavutil/mem.c
> @@ -399,6 +399,18 @@ static void fill32(uint8_t *dst, int len)
>  {
>      uint32_t v = AV_RN32(dst - 4);
>
> +#if HAVE_FAST_64BIT

I suspect this should be !X86_32

> +    uint64_t v2= v + ((uint64_t)v<<32);
> +    while (len >= 32) {
> +        AV_WN64(dst   , v2);
> +        AV_WN64(dst+ 8, v2);
> +        AV_WN64(dst+16, v2);
> +        AV_WN64(dst+24, v2);
> +        dst += 32;
> +        len -= 32;
> +    }

How can I test the performance of this function?

Carl Eugen