[Ffmpeg-devel] [PATCH] h264 - loopify some get_cabac calls

Michael Niedermayer michaelni
Sun Mar 25 05:08:28 CEST 2007


Hi

On Sat, Mar 24, 2007 at 07:23:24PM -0400, Alexander Strange wrote:
> This changes two series of straight-line get_cabac calls to loops.
> 
> Before (skips are intentional):
> 45552 dezicycles in decode_mb_cabac, 8188 runs, 4 skips
> 39043 dezicycles in decode_mb_cabac, 13456 runs, 2928 skips
> 34729 dezicycles in decode_mb_cabac, 23559 runs, 9209 skips
> 32233 dezicycles in decode_mb_cabac, 44016 runs, 21520 skips
> 31117 dezicycles in decode_mb_cabac, 86431 runs, 44641 skips
> 30542 dezicycles in decode_mb_cabac, 171150 runs, 90994 skips
> 30203 dezicycles in decode_mb_cabac, 339742 runs, 184546 skips
> 30131 dezicycles in decode_mb_cabac, 710510 runs, 338066 skips
> 33107 dezicycles in decode_mb_cabac, 1411827 runs, 685325 skips
> 34922 dezicycles in decode_mb_cabac, 2822050 runs, 1372254 skips
> 
> After:
> 45467 dezicycles in decode_mb_cabac, 8188 runs, 4 skips
> 38793 dezicycles in decode_mb_cabac, 13453 runs, 2931 skips
> 34406 dezicycles in decode_mb_cabac, 23555 runs, 9213 skips
> 31879 dezicycles in decode_mb_cabac, 44011 runs, 21525 skips
> 30729 dezicycles in decode_mb_cabac, 86434 runs, 44638 skips
> 30168 dezicycles in decode_mb_cabac, 171152 runs, 90992 skips
> 29826 dezicycles in decode_mb_cabac, 339746 runs, 184542 skips
> 29746 dezicycles in decode_mb_cabac, 710509 runs, 338067 skips
> 32694 dezicycles in decode_mb_cabac, 1411793 runs, 685359 skips
> 34513 dezicycles in decode_mb_cabac, 2822036 runs, 1372268 skips
> 
> Not a big win, but there is a definite one.

could you please run the benchmarks more than once on each, 3 times
is absolute minimum more is better, trent said it in a more obfuscated
way but the benchmark scores of one run only say very little, sure
for you they mean more as you saw more runs likely but we didnt and
as such dont know their variance

note, i did and will ignore all patches with such incomplete benchmarks

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Democracy is the form of government in which you can choose your dictator
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