[Fwd: Re: Off topic - G5 question]

James Cownie jcownie at etnus.com
Mon Jun 30 05:30:37 EDT 2003

Toon Moene wrote :-
> Mark Hahn wrote:
> > I still see users fling their code at a machine with 
> > 	g77 prog.f && ./a.out
> > and wonder why it's so slow.
> Well, I could make -O2 -ffast-math -funroll-loops the default (but then, 
> I don't think I'll get this past the IEEE754 police @ gcc.gnu.org :-)

However there's nothing to stop Mark (assuming he has control of the
machine) from setting the system up so that the "g77" you get by
default is really a shell script which turns on appropriate
optimisation flags, and also providing a command either to compile
unoptimised, or to change the users $PATH so that they can get to a
"raw" g77.

I know that this is the approach used by Nick McLaren on the big Sun
machines at Cambridge. 

Depending on the interests of your users (are they interested in their
application domain, or in becoming compiler switch experts), they may 
prefer a system where someone has already defaulted the compiler to
use an apporpiate set of magic optimisation flags.

-- Jim 

James Cownie	<jcownie at etnus.com>
Etnus, LLC.     +44 117 9071438
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