[mythtv] [patch] mythtv-HOWTO-5.html - compiling for different processors

[manu]

Le 28.12.2004 15:45:14, Isaac Richards a écrit :
> On Tuesday 28 December 2004 03:46 pm, Daniel Thor Kristjansson wrote:
> > On Tue, 28 Dec 2004, Isaac Richards wrote:
> > ]Won't be applied.  Anything but the default compile settings (with
> the
> > ]exception of different arches) is unsupported.
> >
> > This patch removes the -mfpmath=sse performance recommendation, but
> > keeps the additional archs, such as the winchip, the updated C3
> info,
> > and other Intel and AMD processors.
> 
> Have you profiled on each of those processors to see if setting the
> arch
> actually creates faster code?  I've seen -march=athlon-xp create 50%
> slower
> code than -march=pentiumpro with a recent gcc..
> 
> Isaac
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> 

With this version of gcc
gcc (GCC) 3.4.2 20041017 (Red Hat 3.4.2-6.fc3)
I obtained similar results with pentiumpro  and athlon-xp (though the  
athlon code was a bit smaller); but I got a big boost (from 18% of idle  
time to 25 %) when adding HAVE_3DNOW to MMX and also putting -m3dnow on  
the C flags (still with pentiumpro arch).
I have a athlon XP 2000+, and hauppage card, everything is encoded in  
RTJpeg.
Bye
Manu
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