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Message-ID: <ef10de9a0603271333i591b2fa5x3ed8e8cb2c27198c@mail.gmail.com>
Date: Mon, 27 Mar 2006 15:33:09 -0600
From: "Nikolas Britton" <nikolas.britton@gmail.com>
To: "Kris Kennaway" <kris@obsecurity.org>
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Cc: freebsd-stable@freebsd.org
Subject: Re: -march=pentium2 + -mtune=pentium4 faster then -march=pentium4?
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On 3/27/06, Kris Kennaway <kris@obsecurity.org> wrote:
> On Mon, Mar 27, 2006 at 01:05:13PM -0600, Nikolas Britton wrote:
> > Why does GCC produce faster code using "-march=3Dpentium2
> > -mtune=3Dpentium4" on a Pentium 4 chip versus plain -march=3Dpentium4?
> >
> > Try it...
> >
> > CPUTYPE=3Dpentium2
> > CFLAGS+=3D -mtune=3Dpentium4
> > COPTFLAGS+=3D -mtune=3Dpentium4
>
> Talk to the gcc developers (and provide benchmarks).
>

What would be an adequate, proof, benchmark? I've already run several
tests with nbench, testing all of the possible configurations of
-march and -mtune.


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