[mythtv] architecture, compilation and performance

[Matt Zimmerman]

On Sun, Jan 12, 2003 at 10:33:41PM +0000, Mark Cooper wrote:

> I came across this page recently :- http://klicman.org/altivec/ I was 
> quite surprised by the difference shown by the charts comparing 
> performance when compiled with -mcpu=i586 and -mcpu=i686 MMX/SSE. I 
> would guess it would be even greater if -march=athlon-xp were used...

Er...the "MMX/SSE" here refers to hand-optimized MMX/SSE assembly routines,
and has nothing to do with compiling C code.  Note how miniscule the -mcpu
difference is, compared to the assembly functions.  Unless you're explicitly
disabling it in settings.pro, libavcodec is already being built with MMX
support, which uses assembly routines (which are completely unaffected by
compiler optimization flags such as -mcpu).

-- 
 - mdz