[MPlayer-dev-eng] [RFC] disable fastmemcpy on x86-64 by default

[Guillaume Poirier]

Hi,

On May 27, 2007, at 8:15 , Piotr Stachura wrote:

> Dnia niedziela, 27 maja 2007, Reimar D?ffinger napisał:
>> since SSE is part of the x86-64 architecture, at least glibc makes  
>> use
>> of it for its memcpy and some quick (and imprecise) tests indicate  
>> that
>> it's at least not slower.
>> So what do you think about attached patch? Can someone do more  
>> concise
>> benchmarks?
> And what exactly should be "at least not slower". I made simple
> test "-quiet -benchmark -vo null -nosound" and results are following:
>
> w/o patch:
> BENCHMARKs: VC:   9.211s VO:   2.236s A:   0.000s Sys:   0.237s =    
> 11.684s
> BENCHMARK%: VC: 78.8329% VO: 19.1350% A:  0.0000% Sys:  2.0321% =  
> 100.0000%
>
> w/ patch:
> BENCHMARKs: VC:   9.208s VO:   4.087s A:   0.000s Sys:   0.299s =    
> 13.594s
> BENCHMARK%: VC: 67.7354% VO: 30.0667% A:  0.0000% Sys:  2.1979% =  
> 100.0000%
>
> Tests made on AMD64 3000+ (1.8GHz), gcc 4.1.2 and glibc 2.5.

Did you make several runs? Making around 10 runs, providing mean time  
and smallest time would allow to make sure you're not measuring  
random noise.
Also, telling what kind of sample you're using may be a good idea.


All that IMHO.

Guillaume