From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755621AbZECSmU (ORCPT ); Sun, 3 May 2009 14:42:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754855AbZECSmK (ORCPT ); Sun, 3 May 2009 14:42:10 -0400 Received: from terminus.zytor.com ([198.137.202.10]:55411 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752229AbZECSmJ (ORCPT ); Sun, 3 May 2009 14:42:09 -0400 Message-ID: <49FDE47C.7090607@zytor.com> Date: Sun, 03 May 2009 11:37:48 -0700 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.14 (X11/20080501) MIME-Version: 1.0 To: Willy Tarreau CC: Arjan van de Ven , Ingo Molnar , Tobias Doerffel , Thomas Gleixner , Suresh Siddha , "Pallipadi, Venkatesh" , LKML Subject: Re: Specific support for Intel Atom architecture References: <200904301408.09370.tobias.doerffel@gmail.com> <20090430154051.GA3346@elte.hu> <49F9DB70.2050906@zytor.com> <20090503053821.GI570@1wt.eu> <20090503075346.63fc7211@infradead.org> <20090503183038.GA8571@1wt.eu> In-Reply-To: <20090503183038.GA8571@1wt.eu> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Willy Tarreau wrote: >>>> >>>> $(call cc-option,-march=atom,-march=i686) >>> if it's an in-order architecture, wouldn't it be better to tune for >>> i386 or i486 instead ? >> -march isn't about tuning, it's about supported instructions. > > agreed, but unless specified otherwise using -mtune, -march also sets > default tuning for the indicated CPU. At least in my experience. > >> The right line is >> $(call cc-option,-march=atom,-march=core2) For really old gcc's (we support all the way back to gcc 3.2 still) -march=core2 might not work either. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.