[FFmpeg-devel] [PATCH] avcodec/huffman: replace qsort with AV_QSORT

[Ganesh Ajjanagadde]

On Thu, Oct 22, 2015 at 10:25 PM, Ganesh Ajjanagadde
<gajjanagadde at gmail.com> wrote:
>
> On Thu, Oct 22, 2015 at 9:28 PM, Timothy Gu <timothygu99 at gmail.com> wrote:
> > On Thu, Oct 22, 2015 at 5:01 PM Ganesh Ajjanagadde <gajjanagadde at gmail.com>
> > wrote:
> >>
> >> Sample benchmark (x86-64, Haswell, GNU/Linux), fraps-v2 from FATE:
> >> new:
> >> 280110 decicycles in qsort,       1 runs,      0 skips
> >> 268260 decicycles in qsort,       2 runs,      0 skips
> >>
> >> old:
> >> 1469910 decicycles in qsort,       1 runs,      0 skips
> >>  952950 decicycles in qsort,       2 runs,      0 skips
> >
> >
> > Usually it takes more than 2 runs to make sure something is faster than the
> > other (try -stream_loop 10000 on the input).
>
> In this case the gain should be obvious due to inlining. Nevertheless,
> here are new numbers. I chose vp6 for two reasons:
> 1. Above was for fraps-v2, giving vp6 for more "completeness".
> 2. stream_loop throws errors: Error while decoding stream #0:0:
> Invalid data found when processing input for fraps-v2.
>
> Here they are:
> vp6 (old):
>   78930 decicycles in qsort,       1 runs,      0 skips
>   45330 decicycles in qsort,       2 runs,      0 skips
>   27825 decicycles in qsort,       4 runs,      0 skips
>   17471 decicycles in qsort,       8 runs,      0 skips
>   12296 decicycles in qsort,      16 runs,      0 skips
>    9554 decicycles in qsort,      32 runs,      0 skips
>    8404 decicycles in qsort,      64 runs,      0 skips
>    7405 decicycles in qsort,     128 runs,      0 skips
>    6740 decicycles in qsort,     256 runs,      0 skips
>    7540 decicycles in qsort,     512 runs,      0 skips
>    9498 decicycles in qsort,    1024 runs,      0 skips
>    9938 decicycles in qsort,    2048 runs,      0 skips
>    8043 decicycles in qsort,    4095 runs,      1 skips
>
> vp6 (new):
>   15880 decicycles in qsort,       1 runs,      0 skips
>   10730 decicycles in qsort,       2 runs,      0 skips
>   10155 decicycles in qsort,       4 runs,      0 skips
>    7805 decicycles in qsort,       8 runs,      0 skips
>    6883 decicycles in qsort,      16 runs,      0 skips
>    6305 decicycles in qsort,      32 runs,      0 skips
>    5854 decicycles in qsort,      64 runs,      0 skips
>    5152 decicycles in qsort,     128 runs,      0 skips
>    4452 decicycles in qsort,     256 runs,      0 skips
>    4161 decicycles in qsort,     511 runs,      1 skips
>    4081 decicycles in qsort,    1023 runs,      1 skips
>    4072 decicycles in qsort,    2047 runs,      1 skips
>    4004 decicycles in qsort,    4095 runs,      1 skips

ping

>
> >
> > Timothy