Ainsi parlait Gwenole Beauchesne :
On Tue, 18 Mar 2003, Narfi Stefansson wrote:
I believe that Steffen is right that mjpegtools was compiled without MMX in the 9.0 rpms. When I compile for i586 and athlon side by side and I enable MMX for both, I only get a maximum of 10-15% speed difference. The difference in with/without MMX is of course huge :-)
No package will be built with MMX optimizations by default as there are Pentium out there without those extensions. However, if your application dynamically links against some optimized DSOs that would be fine to put those libraries in */lib/mmx/* or */lib/sse{,2}/*. But you will be stuck if they decided to dlopen() their plugins/libraries.
An other option would be to have different packages for optimized and non optimized libs/binaries, and use alternatives to use them transparently.
Would be great i think.
Could the application itself just have runtime detection of CPU features, so you can compile SSE/MMX support in the one package, but it won't try to use it on CPUs that don't support it? I think mplayer does this, and didn't use to.
