From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 19000 invoked by alias); 12 Jul 2011 21:57:37 -0000 Received: (qmail 18991 invoked by uid 22791); 12 Jul 2011 21:57:36 -0000 X-SWARE-Spam-Status: No, hits=-6.2 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_HI,SPF_HELO_PASS,TW_AV,T_RP_MATCHES_RCVD 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; Tue, 12 Jul 2011 21:57:02 +0000 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id p6CLv0ur012825 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Tue, 12 Jul 2011 17:57:01 -0400 Received: from anchor.twiddle.net (vpn-225-164.phx2.redhat.com [10.3.225.164]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id p6CLv0rH012763; Tue, 12 Jul 2011 17:57:00 -0400 Message-ID: <4E1CC32B.3060004@redhat.com> Date: Tue, 12 Jul 2011 22:29:00 -0000 From: Richard Henderson User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110428 Fedora/3.1.10-1.fc15 Thunderbird/3.1.10 MIME-Version: 1.0 To: harsha.jagasia@amd.com CC: gcc-patches@gcc.gnu.org, hubicka@ucw.cz, ubizjak@gmail.com, hjl.tools@gmail.com, Changpeng.Fang@amd.com Subject: Re: AVX generic mode tuning discussion. References: <20110712212201.23194.45716.sendpatchset@gccpike4.amd.com> In-Reply-To: <20110712212201.23194.45716.sendpatchset@gccpike4.amd.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-IsSubscribed: yes Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org X-SW-Source: 2011-07/txt/msg00969.txt.bz2 On 07/12/2011 02:22 PM, harsha.jagasia@amd.com wrote: > We would like to propose changing AVX generic mode tuning to generate 128-bit > AVX instead of 256-bit AVX. You indicate a 3% reduction on bulldozer with avx256. How does avx128 compare to -mno-avx -msse4.2? Will the next AMD generation have a useable avx256? I'm not keen on the idea of generic mode being tune for a single processor revision that maybe shouldn't actually be using avx at all. r~