From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263017AbTJUIWa (ORCPT ); Tue, 21 Oct 2003 04:22:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263018AbTJUIWa (ORCPT ); Tue, 21 Oct 2003 04:22:30 -0400 Received: from dvmwest.gt.owl.de ([62.52.24.140]:38092 "EHLO dvmwest.gt.owl.de") by vger.kernel.org with ESMTP id S263017AbTJUIW2 (ORCPT ); Tue, 21 Oct 2003 04:22:28 -0400 Date: Tue, 21 Oct 2003 10:22:26 +0200 From: Jan-Benedict Glaw To: linux-kernel@vger.kernel.org Subject: Re: [2.6 patch] add a config option for -Os compilation Message-ID: <20031021082225.GA20846@lug-owl.de> Mail-Followup-To: linux-kernel@vger.kernel.org References: <20031015225055.GS17986@fs.tum.de> <20031015161251.7de440ab.akpm@osdl.org> <20031015232440.GU17986@fs.tum.de> <20031015165205.0cc40606.akpm@osdl.org> <20031018102127.GE12423@fs.tum.de> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="pr5L7F0YSlsy7gwk" Content-Disposition: inline In-Reply-To: <20031018102127.GE12423@fs.tum.de> X-Operating-System: Linux mail 2.4.18 X-gpg-fingerprint: 250D 3BCF 7127 0D8C A444 A961 1DBD 5E75 8399 E1BB X-gpg-key: wwwkeys.de.pgp.net User-Agent: Mutt/1.5.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --pr5L7F0YSlsy7gwk Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sat, 2003-10-18 12:21:27 +0200, Adrian Bunk wrote in message <20031018102127.GE12423@fs.tum.de>: > On Wed, Oct 15, 2003 at 04:52:05PM -0700, Andrew Morton wrote: > > I really doubt it. Kernel CPU footprint is dominated by dcache misses.= If > > -Os reduces icache footprint it may even be a net win; people tend to > > benchmark things in tight loops, which favours fast code over small cod= e. >=20 > The main effect of -Os compared to -O2 (besides disabling some > reordering of the code and prefetching) is the disabling of various > alignments. I doubt that's a win on all CPUs. I definively *like* to see -Os be configureable by user. It's *big* win for a lowmem system. There, the actual "running speed" may be limited by HDD swap speed, and having a smaller kernel means having more pages left to luserspace... MfG, JBG --=20 Jan-Benedict Glaw jbglaw@lug-owl.de . +49-172-7608481 "Eine Freie Meinung in einem Freien Kopf | Gegen Zensur | Gegen Krieg fuer einen Freien Staat voll Freier B=FCrger" | im Internet! | im Ira= k! ret =3D do_actions((curr | FREE_SPEECH) & ~(NEW_COPYRIGHT_LAW | DRM | TC= PA)); --pr5L7F0YSlsy7gwk Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.3 (GNU/Linux) iD8DBQE/lOzBHb1edYOZ4bsRAhSVAJ0dvhtjPMIuxzd58bOGur9PYZ43ywCeKTUd K3C2rUAtqm2U72uYGOc0qr0= =A/7S -----END PGP SIGNATURE----- --pr5L7F0YSlsy7gwk--