Optimisation

Seth W. Klein sklein at mint.net
Tue Sep 5 09:34:28 PDT 2000


Simon Perreault wrote:

> On Mon, 04 Sep 2000, Chris Gianelloni wrote:
> > The main problem I have is that I am not familiar with exactly *what* may be causing the problem.  I was more or less asking if there are any
> > packages that anyone KNOWS offhand doesn't work at such high optimisations.  I am really wanting everything possible to be optimised.  Is it
> > possible to use optimisations when compiling glibc or should I compile it with the default -O2 (maybe -O3)
> 
> Shared bash can't be optimized higher than -O2 without segfaulting. I've tested
> it.

But so have i, and it works :) I've used it under chroot with a glibc
also compiled with `-O3 -march=i586'. _That_ really shouldn't work. I
have no way of checking, but i'd be surprised if the bash i'm using
now wasn't also optimized.

I'm afraid Gerard is right. There's no way to know without trying it.
What works for me may not for you. Things that have me tearing my
hair out, you may not even know you optimized.

Is it worth it? There again, only you would know. If you're short on
hair, you may be better off with `-O -march=i386'. (That's extreme,
i know. Most packages specify -O2 themselves.) But if you're running
a loaded database server, testing higher optimizations could be the
whole reason they hired you.

cheers,
sklein
--
sklein at mint.net                          http://members.mint.net/sklein/






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