From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 13943 invoked by alias); 5 Oct 2006 16:08:44 -0000 Received: (qmail 13920 invoked by uid 22791); 5 Oct 2006 16:08:43 -0000 X-Spam-Check-By: sourceware.org Received: from mx1.redhat.com (HELO mx1.redhat.com) (66.187.233.31) by sourceware.org (qpsmtpd/0.31) with ESMTP; Thu, 05 Oct 2006 16:08:32 +0000 Received: from int-mx1.corp.redhat.com (int-mx1.corp.redhat.com [172.16.52.254]) by mx1.redhat.com (8.12.11.20060308/8.12.11) with ESMTP id k95G8TSS015075; Thu, 5 Oct 2006 12:08:29 -0400 Received: from pobox.toronto.redhat.com (pobox.toronto.redhat.com [172.16.14.4]) by int-mx1.corp.redhat.com (8.12.11.20060308/8.12.11) with ESMTP id k95G8Tdw006032; Thu, 5 Oct 2006 12:08:29 -0400 Received: from redhat.com (torque.toronto.redhat.com [172.16.14.46]) by pobox.toronto.redhat.com (8.12.8/8.12.8) with ESMTP id k95G8TY7005755; Thu, 5 Oct 2006 12:08:29 -0400 Message-ID: <45252DFC.1060505@redhat.com> Date: Thu, 05 Oct 2006 16:08:00 -0000 From: Vladimir Makarov User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.2.1) Gecko/20030225 MIME-Version: 1.0 To: Ian Lance Taylor CC: Jan Dillmann , gcc-help@gcc.gnu.org Subject: Re: gcc 3.4.3: -march optimization for Intel Core2Duo References: <63AFD0B111A746449C6F215251DE622A03B225@ibrserv01> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes Mailing-List: contact gcc-help-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Archive: List-Post: List-Help: Sender: gcc-help-owner@gcc.gnu.org X-SW-Source: 2006-10/txt/msg00041.txt.bz2 Ian Lance Taylor wrote: >"Jan Dillmann" writes: > > > >>we are running several benchmarks (SpecCPU200...) on 32-bit linux-systems and are able to set an optimization-parameter >>for '-march'. We use Intel Core2uo-CPUs. Which parameter should we use (nocona, prescott...) ? >> >> > >gcc 3.4.3 has no specific tuning for Core2 Duo, if for no other reason >than the release was made before the processors became available. My >guess would be that you will get the best results with -mtune=nocona. >But it is only a guess. > > > I believe that pentium-m will work better. Nocona (a x86_64 processor) is based on northwood/prescott core which is a high frequency core with long pipelines. Core2 Duo is closer to pentium M (lower frequency core with much shorter pipelines). Although usage of penium-m will result a bigger code in comparison with nocona because aligning loop/function will be forced (nortwood core is not so sensitive to aligning therfore aligining is not done when -mtune=nocona is used). I don't remember Intel recomendation about aligning code for Core Duo (probably it is the same as for penium M).