From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 17500 invoked by alias); 7 Sep 2011 16:24:17 -0000 Received: (qmail 17480 invoked by uid 22791); 7 Sep 2011 16:24:12 -0000 X-SWARE-Spam-Status: No, hits=-6.6 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_HI,RP_MATCHES_RCVD,SPF_HELO_PASS X-Spam-Check-By: sourceware.org Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Wed, 07 Sep 2011 16:23:56 +0000 Received: from int-mx12.intmail.prod.int.phx2.redhat.com (int-mx12.intmail.prod.int.phx2.redhat.com [10.5.11.25]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id p87GNt8R005745 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Wed, 7 Sep 2011 12:23:55 -0400 Received: from toll.yyz.redhat.com (toll.yyz.redhat.com [10.15.16.165]) by int-mx12.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id p87GNsnM031875 for ; Wed, 7 Sep 2011 12:23:55 -0400 Message-ID: <4E679A9A.1070408@redhat.com> Date: Wed, 07 Sep 2011 16:24:00 -0000 From: Vladimir Makarov User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.18) Gecko/20110621 Fedora/3.1.11-1.fc14 Thunderbird/3.1.11 MIME-Version: 1.0 To: gcc@gcc.gnu.org Subject: Re: Comparison of GCC-4.6.1 and LLVM-2.9 on x86/x86-64 targets References: <4E678A9B.3040303@redhat.com> 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@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-owner@gcc.gnu.org X-SW-Source: 2011-09/txt/msg00047.txt.bz2 On 09/07/2011 11:55 AM, Xinliang David Li wrote: > Why is lto/whole program mode not used in LLVM for peak performance > comparison? (of course, peak performance should really use FDO..) > Thanks for the feedback. I did not manage to use LTO for LLVM as it described on http://llvm.org/docs/LinkTimeOptimization.html#lto I am getting 'file not recognized: File format not recognized' during the linkage pass. You probably right that I should use -Ofast without -flto for gcc then. Although I don't think that it significantly change GCC peak performance. Still I am going to run SPEC2000 without -flto and post the data (probably on the next week). As for FDO, unfortunately for some tests SPEC uses different training sets and it gives sometimes wrong info for the further optimizations. I do not look at this comparison as finished work and am going to run more SPEC2000 tests and change the results if I have serious reasonable objections for the current comparison.