$HOSTTYPE and related topics.

[Alexander Dalloz]

Am Di, den 13.01.2004 schrieb Matt H. um 02:57:
> On Mon, 12 Jan 2004 09:04:33 -0300, Alexandre Strube wrote:
> 
> > Take a look at which kernel version you're using...
> 
> I currently have kernel 2.4.22-1.2140.nptl. Do you mean what architecture
> it was compiled for? In that case, "athlon". That's why I thought
> $HOSTTYPE and $MACHTYPE should reflect this.
> 
>  On Mon, 12 Jan 2004 18:09:31 +0100, Alexander Dalloz wrote:
> 
> > What you see on you Athlon system is the situation and ok. Fedora Core 1
> > is still i386 based, only glibc may vary like on your's which is i686,
> > and the kernel is CPU dependent compiled. You see last by using "uname
> > -a".
> 
> So it's common to use the generic "i386" branding even with today's
> generation processors and architecture? 

Well, you can build a whole system to a more reacent architecture type
like i686, but as far as I read about, you will not gain significant
improvents. The Gentoo guys, which love their compiling around the clock
for speed gains, could never proove the performance boost. I am sure it
is a myth. On gentoo.org itself you can see some values about different
compiled systems and their response time and it showed me, that their is
at best a statistical difference.

> > What do you expect by having a i686 based architecture compile? You
> > might only gain just a few percentages of speed, if though.
> 
> If I was to recompile my kernel for "i686" or "athlon", this would not be
> beneficial to system performance and efficiencies?

It is a difference to build a kernel with right switch for your
processor type and to build normal applications with architecutre
compiler flags.

> > As far as I see at the rpm macros, Fedora is using prelinking, which
> > normally brings you most performance gains using different applications.
> 
> This prelinking you mentioned is interesting. I read the howto you linked
> to and would like to investigate more with it. Can you tell me if it is
> done internally or must I manually enter `/uss/sbin/prelink -afmR` in
> order to use this feature? 

Sorry, I am no gcc professionel. the prelink package on Fedora is
maintained by jakub at redhat.com. I think it would be helpful if he or
some other compiler guys would reply to your question. But prelinking
should be active if you look at

-rw-r--r--    1 root     root       267839 12. Jan 04:02
/etc/prelink.cache
-rw-r--r--    1 root     root          669  1. Jul 2003 
/etc/prelink.conf

So prelink.cache is written on maintenance run every moring at 4:02 by
the daily cron run and library directories are defined in prelink.conf.

> > Alexander
>
> Matt

Regards

Alexander


-- 
Alexander Dalloz | Enger, Germany
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