[XviD-devel] More MMX improvements

Pascal Massimino skal at planet-d.net
Thu Jul 28 23:54:40 CEST 2005


	Howdy everybody,

On Thu, 2005-07-28 at 22:38, Guillaume POIRIER wrote:
> Hi,
> 
> On 7/17/05, carlo.bramix <carlo.bramix at libero.it> wrote:
> > Hello,
> > I did more improvements to:
> > 
> > \xvid_20050712\xvidcore\src\bitstream\x86_asm\cbp_mmx.c
> > 
> > This new version is 6.2% to 7.4% faster if compared to the same source into the CVS.
> > I attached this new patch here.
> 
> Your optimization do work for me, but I can't measure any speed-up.
> You must be optimizing a part of XviD that doesn't account for a large
> part of the encoding process.
> 
> Now, I don't know what the maintainers are gonna do about it, but I'm
> quite worried about the fact that no one has commented on that patch.
> :-(

	It's on my to-commit list ... when holidays are over :)
	Anyway, it's normal and expected you don't see any
	speed-up. Cbp calculation is called once per MB. Would
	it not be in MMX/SSE, but simply plain C, you wouldn't
	notice the difference either. 
	*But*, i personally find it very pleasant lot of people
	try to optimize this particular function. 
	Hey, where would be the fun of open-sourceness
	otherwise, hmm? :)

	i'll try to find some time to do my homework...

	bye!
Skal





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