[gentoo-performance] Re: getting athlon-xp/geforce4 system "on the top"

[MAL]

Koby Boy wrote:
> On Tue, 2003-05-06 at 03:24, eNTi wrote:
>>CFLAGS="-mcpu=athlon-xp -O3 -pipe -m3dnow -msse -mmmx -Wall -fomit-frame-pointer" / CHOST="i686-pc-linux-gnu"
>
> I've got an Athon-XP 2400 (2 GHz) but I've over clocked it to the
> equivalent of an Athlon-XP 2600 (2.2GHz).  My CFLAGS look like this:
>
> CFLAGS="-mcpu=athlon-xp -march=athlon-xp -O3 -fforce-addr
> -fomit-frame-pointer -funroll-loops -frerun-cse-after-loop
> -frerun-loop-opt -falign-functions=4 -foptimize-sibling-calls
> -fexpensive-optimizations -pipe -m3dnow -mmmx -msse -mfpmath=sse,387"

-march=athlon-xp implies:
   -mcpu=athlon-xp

-march=athlon-xp implies:
   -m3dnow
   -mmmx
   -msse

-O3 implies -O2 which implies:
   -frerun-loop-opt
   -frerun-cse-after-loop
   -frerun-loop-opt
   -falign-functions
   -fexpensive-optimizations

-mfpmath=sse,387 is still unstable.. asking for trouble!

Lastly, many people have expressed that -funroll-loops slows down more 
code than it speeds up.

I'd be surprised if you see much improvement over '-O3 -pipe', in 99% of 
apps, not worth it's time in debugging broken code :/

man gcc *g*

MAL


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