[RULE] Is it worth rebuilding from source RPMs for a specific CPU type?

[M. Fioretti]

On Tue, Apr 29, 2003 17:06:07 at 05:06:07PM -0400, C David Rigby  cdrigby at 9online.fr  wrote:
> Above and beyond the issue of the lack of an "i386" kernel in later
> versions of RedHat, I am wondering if there is any significant
> performance advantage to compiling the source RPMs (SRPMS) for a
> specific processor. 
I have read several times that this makes a difference only for those
programs and libs that can use the instructions and capabilities of
those better processors, and that usually this means multimedia
stuff. In other words, a recompiled find, grep, or emacs may show no
difference at all, xine or xmms may (may!) go sensibly faster.

> 
> I am assuming that the rpm "--rebuild" option or rpmbuild, depending on
> the version of rpm used, actually cares about and optimizes for a
> particular Intel CPU family, depending on the CPU installed in the
> computer.

My understanding is that you have to write it in the makefile, ie that
rpm is not so smart and daring to jump over you and say "lemme
optimize this". Which, if confirmed, sounds much more sensible if you
ask me.

I think that you should check the shrike archives, and then ask
there. IIRC, there are people trying and discussing this very issue
for any release of every distro since when the Pentium appeared, but
I've never followed them really closely.

     Ciao,
		Marco Fioretti

-- 
Marco Fioretti                 mfioretti
Red Hat for low memory         www.rule-project.org

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                                                       R. A. Heinlein


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