RFC: Fedora Extras shipping ix86 optimized rpms?

dragoran dragoran at feuerpokemon.de
Wed Sep 1 08:19:10 UTC 2004


Jakub Jelinek schrieb:

>On Tue, Aug 31, 2004 at 05:38:31PM +0200, Matthias Saou wrote:
>  
>
>>Is then having the same library twice, the regular one in /usr/lib and the
>>SSE2 optimized one in /usr/lib/sse2, expected to "just work" at runtime? If
>>    
>>
>
>Yes, it will just work.
>Both the dynamic linker and ldconfig know how to handle it.
>
>  
>
>>so, I didn't know the existence of this, and will definitely look into it.
>>What about MMX? Should one just simplify with SSE vs. non-SSE instead and
>>put (non runtime) MMX optimized libs there too?
>>    
>>
>
>ATM sse2 is the only "important" feature ld.so on IA-32 handles.
>Previously it used to be mmx, but as every added feature slows down
>library loading when not using ld.so.cache (e.g. when LD_LIBRARY_PATH
>is used or DT_RPATH; every feature doubles the number of stat'ed
>directories before the non-existing directory cache is filled),
>it was just changed to sse2 instead of adding sse2 to mmx.
>SSE2 was chosen because you can get quite a big speedup already
>by recompiling with -msse2 -mfpmath=sse.
>
>	Jakub
>
>
>  
>
and what about -m3dnow on amd systems ?





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