[mythtv] CPU Optimisation

[Andrew Mahone]

On Apr 7, 2005 3:19 PM, Robert Johnston <anaerin at gmail.com> wrote:
> Just out of interest, what's the difference between "athlon" and
> "athlon-xp" profiles in gcc? And which should a Socket A Sempron
> (Barton core) be using? I've compiled with -march=athlon-xp and had no
> lockups yet...

The Barton is an Athlon XP core - essentially, Sempron is (in Socket
A) the new name for Athlon XP.  This is a bit confusing, as the Socket
754 version is an Athlon 64 core with 64-bit mode disabled.  IIRC the
difference between the XP and previous Athlon cores is the addition of
SSE (one only, not SSE2) instructions.  There may be some differences
in optimal instruction ordering that I don't know about.

I've also heard that the XP CPU model in GCC is a bit broken, and that
the Pentium3 one (-march=pentium3, and it support the same instruction
set extensions, except for 3DNow!) actually produces better code for
Athlon XP.  You might want to test that yourself, it's only something
I heard.

-- 
Andrew Mahone
andrew DOT mahone AT gmail DOT com