From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 18934 invoked from network); 8 Sep 2004 10:16:21 +0000 Received: from smtp.gentoo.org (156.56.111.197) by lists.gentoo.org with AES256-SHA encrypted SMTP; 8 Sep 2004 10:16:21 +0000 Received: from lists.gentoo.org ([156.56.111.196] helo=parrot.gentoo.org) by smtp.gentoo.org with esmtp (Exim 4.34) id 1C4zUy-0004j9-Gp for arch-gentoo-dev@lists.gentoo.org; Wed, 08 Sep 2004 10:16:20 +0000 Received: (qmail 3898 invoked by uid 89); 8 Sep 2004 10:16:14 +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 21880 invoked from network); 8 Sep 2004 10:16:13 +0000 Message-ID: <33333.10.0.0.51.1094638559.squirrel@10.0.0.51> Date: Wed, 8 Sep 2004 12:15:59 +0200 (CEST) From: "Klavs Klavsen" To: gentoo-dev@lists.gentoo.org User-Agent: SquirrelMail/1.4.3a X-Mailer: SquirrelMail/1.4.3a MIME-Version: 1.0 Content-Type: text/plain;charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-Priority: 3 (Normal) Importance: Normal X-Virus-Scanned: by amavisd-new at enableit.dk Subject: [gentoo-dev] Do we want optimal performance? X-Archives-Salt: 94bc7ab3-07b9-4f76-884e-d9d18d623a98 X-Archives-Hash: 24d97420d14fa76b263b6ae45bccce12 Hi guys, Just read an interesting article about Xeon vs. Opteron from anandtech - where they really show how much difference compile optimizations (or not) does - and how it differs for different programs for different processors. http://www.anandtech.com/linux/showdoc.aspx?i=2163&p=1 To me this clearly shows, that if Gentoo wants the best performance - we can't use a "one cflags fits them all" approach. I do know that if a program breaks, those CFLAGS are pulled out in the individual ebuild, but this is not due to poor performance. IMHO the only way for Gentoo to prove its true potential - is to somehow build an array of compile options, with CPU's on X, programs on Y and GCC-version on Z. Getting the numbers for each CPU, will ofcourse require writing tests, for each program - but IMHO this can be done, if we do it one at a time. I would suggest these tests be included like the gentoo-stats program, as something the individual Gentooist can choose to run after each compile - which would give him the optimal performance (and recompile X number of times to test different flags out) on his CPU/program/GCCversion combination, and at the same time, send the result to a Gentoo database. I know I would definetely have the patience to let it test and test again, if it meant more performance for me Smile The end result should be, that Gentoo automagically selects the optimal CFLAGS (in performance and stability - perhaps with some optimizations flagged as "unstable" so people can select "optimize for performance" vs. "optimize for stability") depending on the X, Y and Z from above. I would very much like to be one of the guys that gets the ball rolling, but as I'm not a Gentoo Dev - We (or just I) need to agree with the Gentoo Dev's on how this could best be done. What do you think? am I crazy? It seems to me that the anandtech tests shows that it is more than just a 1% or 2% difference, with the right CFLAGS - and that the right CFLAGS for one program, can be the worst for another on same CPU/GCC combination. -- Regards, Klavs Klavsen, GSEC - kl@vsen.dk - http://www.vsen.dk PGP: 7E063C62/2873 188C 968E 600D D8F8 B8DA 3D3A 0B79 7E06 3C62 "Those who do not understand Unix are condemned to reinvent it, poorly." --Henry Spencer -- gentoo-dev@gentoo.org mailing list