[FFmpeg-devel] [PATCH] Optimization of original IFF codec

Sebastian Vater cdgs.basty
Tue Apr 27 04:44:08 CEST 2010

Michael Niedermayer a ?crit :
> On Mon, Apr 26, 2010 at 06:40:19PM -0400, Ronald S. Bultje wrote:
>> Applied.
> benchmark of before and after this patch?
> it adds code duplication and its not clear if it would be faster as it
> does not change the inner loop
> [...]

I got a speedup of 1-2% using this (we discussed this on IRC)...

I think it will be much more effective with my high optimization
patches, because inlining these vastly increases the chance that the
whole loop will still go into the code cache (killing all the branches
makes the whole loop stuff much shorter and the branch prediction can't
get wrong).

I measured this by adding a loop counter from 0 to 1.000.000 around the
outer-loop using START_TIMER before and STOP_TIMER after it. So it
should be pretty precise. ;-)


Best regards,
                   :-) Basty/CDGS (-:

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