From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 31324 invoked by uid 1002); 14 Aug 2003 10:10:59 -0000 Mailing-List: contact gentoo-dev-help@gentoo.org; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-dev@gentoo.org Received: (qmail 12257 invoked from network); 14 Aug 2003 10:10:58 -0000 From: Paul de Vrieze To: gentoo-dev@gentoo.org Date: Thu, 14 Aug 2003 12:10:57 +0200 User-Agent: KMail/1.5.3 References: <1060781901.7508.17.camel@biproc> <1060809305.3784.2.camel@localhost> <1060814942.27241.148.camel@rattus.Localdomain> In-Reply-To: <1060814942.27241.148.camel@rattus.Localdomain> MIME-Version: 1.0 Content-Type: multipart/signed; protocol="application/pgp-signature"; micalg=pgp-sha1; boundary="Boundary-02=_xA2O/OOmZM2/iOJ"; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <200308141210.57530.pauldv@gentoo.org> Subject: Re: [gentoo-dev] "Distro Day (Measuring the benefits of the Gentoo approach)" X-Archives-Salt: 5cb7d870-ee70-49f0-af37-5002efb77acb X-Archives-Hash: 867a45c4e07b9ab13797ff5f1017e8b0 --Boundary-02=_xA2O/OOmZM2/iOJ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Content-Description: signed data Content-Disposition: inline > We may be getting a P4 hyperthreaded system to play with, but under > different rules, where I get to do a bit of tuning first. I have > already built the core system on another machine using gcc-3.2.3, > "-march=3Dpentium4 -O3 -pipe -fomit-frame-pointer" I note that the > pentium4 warning still appears in make.conf, though I believe it no > longer applies to this gcc. > > A while ago I emailed this list and asked for information on tests and > settings for HT P4's, without a reply. So again, has anyone done any > tests on a HT P4 and is willing to support the flags they chose as being > "the best"? In particular, does -ffast-math give a measurable gain? > Most of my machines have been built as scientific stations, so accuracy > is more important than ultimate speed, so this is one I have never > tested. I am not interested in the -O9 -max-everything kiddies who have > been so vocal, but reasoned choices. > > If you want to flame, go ahead - but support your statements! Well all packages that cannot handle -march=3Dpentium4 should filter it out= =2E=20 This filtering is imprefect so adding -mcpu=3Dpentium4 should ensure correc= t=20 scheduling of all packages. One thing, do not use -ffast-math, as can be se= en=20 in the manual this can actually produce mathematic errors. Normally one doe= s=20 not want this in most packages, so leave it alone. It could be used in thin= gs=20 like games, wher the precision does not matter that much, but it is not saf= e=20 as a default. Paul =2D-=20 Paul de Vrieze Gentoo Developer Mail: pauldv@gentoo.org Homepage: http://www.devrieze.net --Boundary-02=_xA2O/OOmZM2/iOJ Content-Type: application/pgp-signature Content-Description: signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.2 (GNU/Linux) iD8DBQA/O2AxbKx5DBjWFdsRAhAMAKDE3JUi1LNFpkepRGkn0BtCM+UCQgCgmCE/ 0EeVVqHYWKk9fdc9Yvpvo2I= =KLW/ -----END PGP SIGNATURE----- --Boundary-02=_xA2O/OOmZM2/iOJ--