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

[manu]

Le 28.12.2004 16:12:56, Daniel Thor Kristjansson a écrit :
> On Tue, 28 Dec 2004, Isaac Richards wrote:
> ]> 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
> 
> No, I only have Intel processors at my disposal. Compiling for
> pentium4
> gives me a 30% speed boost. For the rest, I based this on the gcc
> manual. I've heard rumors about xp optimization being broken, but I
> can't verify this myself.
> 
> I made this patch to the documentation because someone was having
> problems compiling mmx_gcc.cpp because they were targeting the
> pentiumpro, which did not support MMX. The compiler, rightly, did
> not generate the MMX code.

Well I have an AMD XP so I could compile with the two different arch  
flags, question is: how do you measure the difference (for now I just  
basically stare at top during liveTV, but I guess there's something  
more scientific ;-).
Bye
Manu
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: not available
Url : http://mythtv.org/pipermail/mythtv-dev/attachments/20041230/3673550c/attachment.pgp