Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266071AbUAFGHZ (ORCPT ); Tue, 6 Jan 2004 01:07:25 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266072AbUAFGHZ (ORCPT ); Tue, 6 Jan 2004 01:07:25 -0500 Received: from unthought.net ([212.97.129.88]:8415 "EHLO unthought.net") by vger.kernel.org with ESMTP id S266071AbUAFGHY (ORCPT ); Tue, 6 Jan 2004 01:07:24 -0500 Date: Tue, 6 Jan 2004 07:07:22 +0100 From: Jakob Oestergaard To: Tomas Szepe Cc: Mikael Pettersson , akpm@osdl.org, linux-kernel@vger.kernel.org Subject: Re: Pentium M config option for 2.6 Message-ID: <20040106060722.GA27889@unthought.net> Mail-Followup-To: Jakob Oestergaard , Tomas Szepe , Mikael Pettersson , akpm@osdl.org, linux-kernel@vger.kernel.org References: <200401041227.i04CReNI004912@harpo.it.uu.se> <20040104123358.GB24913@louise.pinerecords.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040104123358.GB24913@louise.pinerecords.com> User-Agent: Mutt/1.3.28i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1258 Lines: 35 On Sun, Jan 04, 2004 at 01:33:58PM +0100, Tomas Szepe wrote: > On Jan-04 2004, Sun, 13:27 +0100 > Mikael Pettersson wrote: > > > IOW, don't lie to the compiler and pretend P-M == P4 > > with that -march=pentium4. > > What do you recommend to use as march then? There is > no pentiumm subarch support in gcc yet; I was convinced > p4 was the closest match. Use the same as for P-III. The P-M has the same instruction decoder (and execution unit) setup as the P-III, which is *very* different from P-IV (which has one decoder only, and then a trace cache for the decoded uops). This is an important difference from a code generator point of view. >From reading Intel's optimization guides, it seems to me like the P-M is pretty much just a slightly enhanced P-III (more cache AFAIR) which happens to get shipped with a good mobile chipset - and that package together is called Centrino. That would also explain why Centrino leaves the P-IV based laptops in the dust ;) Cheers, / jakob - 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/