[Ffmpeg-cvslog] r6586 - in trunk/libavcodec: cabac.c cabac.h h264.c

Uoti Urpala uoti.urpala
Mon Oct 9 01:52:48 CEST 2006

On Mon, 2006-10-09 at 01:19 +0200, Michael Niedermayer wrote:
> > On Athlon the C version "*state= c->mps_state[s];" (without the other
> > redundant C there) is faster than the asm. The difference is small,
> > around 0.3%, but the times do seem consistent.
> with START/STOP_TIMER? without it such small differences are meaningless
> IMO, they could be caused by arrays or functions ending up at slightly
> more favorable addresses or such aka systematic error

Without. It certainly could be some such "random effect". However I
think the results from START/STOP_TIMER would be an even less reliable
indicator when comparing which version would be "better in general". The
function is inlined in several places and doesn't use that much time per
call, so trying to separate the extra time caused by it from from the
function it's inlined in could easily have inaccuracies bigger than 3%
(0.3% * 10, assuming roughly 10% of time spent in get_cabac).

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