Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760774AbXJZLpB (ORCPT ); Fri, 26 Oct 2007 07:45:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759685AbXJZLom (ORCPT ); Fri, 26 Oct 2007 07:44:42 -0400 Received: from emailhub.stusta.mhn.de ([141.84.69.5]:37126 "EHLO mailhub.stusta.mhn.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1759583AbXJZLol (ORCPT ); Fri, 26 Oct 2007 07:44:41 -0400 Date: Fri, 26 Oct 2007 13:45:10 +0200 From: Adrian Bunk To: =?utf-8?Q?P=C3=A1draig?= Brady Cc: Michael Lothian , linux-kernel@vger.kernel.org Subject: Re: Possibility of adding -march=native to x86 Message-ID: <20071026114510.GD30533@stusta.de> References: <0EC33A59AA72084CA28B83816B40929F02682BB3@REEDXCLSXM01V03.rbsres01.net> <20071025185022.GP30533@stusta.de> <20071025191723.GQ30533@stusta.de> <20071025195020.GS30533@stusta.de> <20071025202031.GU30533@stusta.de> <4721C44E.4000800@draigBrady.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <4721C44E.4000800@draigBrady.com> User-Agent: Mutt/1.5.16 (2007-06-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1421 Lines: 37 On Fri, Oct 26, 2007 at 11:41:18AM +0100, Pádraig Brady wrote: > Adrian Bunk wrote: > > On Thu, Oct 25, 2007 at 09:12:45PM +0100, Michael Lothian wrote: > >>> The MPENTIUM4 option does not only set -march=pentium4, it also enables > >>> several other options in arch/i386/Kconfig.cpu resulting in better > >>> performance. > >> How about an autodetect to set the right options here too using cpuid? > >> > >> With a warning of course that the code produced will be specifically > >> for the native cpu that it's compiled on. > > > > If you don't know or can figure out yourself the CPU you have, you'd > > better not compile your own kernel... > > There also is the added variable of what your version of gcc supports. > The kernel gcc options would have to be the highest common factor. > See also http://www.pixelbeat.org/scripts/gcccpuopt arch/i386/Makefile.cpu already does more or less the same. > Pádraig. cu Adrian -- "Is there not promise of rain?" Ling Tan asked suddenly out of the darkness. There had been need of rain for many days. "Only a promise," Lao Er said. Pearl S. Buck - Dragon Seed - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/