Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759627AbXJYVqc (ORCPT ); Thu, 25 Oct 2007 17:46:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752800AbXJYVqU (ORCPT ); Thu, 25 Oct 2007 17:46:20 -0400 Received: from mailout.stusta.mhn.de ([141.84.69.5]:55698 "EHLO mailhub.stusta.mhn.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1759003AbXJYVqT (ORCPT ); Thu, 25 Oct 2007 17:46:19 -0400 Date: Thu, 25 Oct 2007 23:46:47 +0200 From: Adrian Bunk To: Michael Lothian Cc: Gabriel C , linux-kernel@vger.kernel.org Subject: Re: Possibility of adding -march=native to x86 Message-ID: <20071025214647.GX30533@stusta.de> References: <0EC33A59AA72084CA28B83816B40929F02682BB3@REEDXCLSXM01V03.rbsres01.net> <20071025185022.GP30533@stusta.de> <20071025191723.GQ30533@stusta.de> <20071025195020.GS30533@stusta.de> <4720FF2B.9020802@googlemail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: 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: 2020 Lines: 58 On Thu, Oct 25, 2007 at 10:30:09PM +0100, Michael Lothian wrote: > On 25/10/2007, Gabriel C wrote: > > 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. > > > > And kill off all Distro kernels right ? IMO to set that auto magically is bad. > > > > Regards, > > > > Gabriel > > > Yes for something like a distro kernel it is bad but as I said before > this isn't what this is for. > > Eventually it would be nice to to a make localkernel and for a > customised kernel to be build compiling in all pci / pci express > drivers into the kernel and all usb devices as modules. > > Auto magically detecting the cpu would be part of that > > I hate getting a new piece of kit and then have to figure out from > lspci which options need to be turned on and the the really iritation > part of finding the option in make menuconfig What exactly is irritating? Please name the problems so that they can be fixed. > Detecting the cpu and using march=native could be all part of that You don't need march=native for this. You have to set the right config option for your CPU and you automatically get the right compiler options. > Mike 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/