Date: Thu, 14 Sep 2006 01:01:33 -0400
From: Kris Kennaway <kris@obsecurity.org>
To: Gary Kline <kline@sage.thought.org>
Cc: Tony Maher <anthony.maher@uts.edu.au>, freebsd-stable@freebsd.org, Stefan Lambrev <stefan.lambrev@sun-fish.com>
Subject: Re: optimization levels for 6-STABLE build{kernel,world}
Message-ID: <20060914050133.GA26618@xor.obsecurity.org>
In-Reply-To: <20060914045725.GB92358@thought.org>
References: <200609130905.k8D95idk062789@lurza.secnetix.de> <4507CC9B.60704@sun-fish.com> <20060913234934.GA92067@thought.org> <45089D47.6070005@uts.edu.au> <20060914045725.GB92358@thought.org>
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--2oS5YaxWCcQjTEyO Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Sep 13, 2006 at 09:57:25PM -0700, Gary Kline wrote: > On Thu, Sep 14, 2006 at 10:07:35AM +1000, Tony Maher wrote: > > Gary Kline wrote: > >=20 > > > <deleted> > > > > > > A couple of things. Will having gcc unroll loops have any > > > negative consequences? (I can't imagine how:: but better=20 > > > informed than to have something crash inexplicability.) > > > With 6.X safe at -O2 and with -funroll-loops, that should be > > > a slight gain, right? (It also will make an upgrade from 5.5=20 > > > to 6.[12] that much more rational.) > >=20 > > -funroll-loops affect loader see > > http://lists.freebsd.org/pipermail/freebsd-stable/2006-September/028145= .html > >=20 >=20 > Right. This is probably what Chuck Swiger was talking about. > I've never had this problems on my 5.[345] releases. And not > with 6.1 (knock-wood!!).=20 >=20 > I've just upgraded to -RELEASE and going to rebuild overnight on > the server that traped out. With -funroll-loops gone :-) Just leave it alone unless you know what you're doing...fiddling with the compiler flags just isn't going to give you a secret performance boost for general workloads, no matter how cool it might make you feel :) Kris --2oS5YaxWCcQjTEyO Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (FreeBSD) iD8DBQFFCOIsWry0BWjoQKURAjp+AKD7LQQZMDV0Vz/FyxStvzRqu+MAAwCgyweA GC93zK7LS0GR7YX3k9G6vrs= =gYjq -----END PGP SIGNATURE----- --2oS5YaxWCcQjTEyO--
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