From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 15172 invoked by alias); 25 Mar 2011 15:33:53 -0000 Received: (qmail 15160 invoked by uid 22791); 25 Mar 2011 15:33:52 -0000 X-SWARE-Spam-Status: No, hits=-6.4 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_HI,SPF_HELO_PASS,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; Fri, 25 Mar 2011 15:33:48 +0000 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id p2PFXeib029492 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Fri, 25 Mar 2011 11:33:40 -0400 Received: from tyan-ft48-01.lab.bos.redhat.com (tyan-ft48-01.lab.bos.redhat.com [10.16.42.4]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id p2PFXdkm010446 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 25 Mar 2011 11:33:40 -0400 Received: from tyan-ft48-01.lab.bos.redhat.com (localhost.localdomain [127.0.0.1]) by tyan-ft48-01.lab.bos.redhat.com (8.14.4/8.14.4) with ESMTP id p2PFXdN5012656; Fri, 25 Mar 2011 16:33:39 +0100 Received: (from jakub@localhost) by tyan-ft48-01.lab.bos.redhat.com (8.14.4/8.14.4/Submit) id p2PFXcOD012654; Fri, 25 Mar 2011 16:33:38 +0100 Date: Fri, 25 Mar 2011 15:35:00 -0000 From: Jakub Jelinek To: Jeff Law Cc: Michael Matz , Aldy Hernandez , Richard Guenther , Andrew MacLeod , "Joseph S. Myers" , Richard Henderson , gcc-patches Subject: Re: [cxx-mem-model] disallow load data races (1 of some) Message-ID: <20110325153338.GZ18914@tyan-ft48-01.lab.bos.redhat.com> Reply-To: Jakub Jelinek References: <4D8B8051.2030307@redhat.com> <4D8BA278.8000300@redhat.com> <4D8BB82F.3060901@redhat.com> <4D8BDA6F.2090304@redhat.com> <4D8C9140.3020506@redhat.com> <4D8CB50E.1070207@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4D8CB50E.1070207@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) 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: 2011-03/txt/msg01752.txt.bz2 On Fri, Mar 25, 2011 at 09:30:22AM -0600, Jeff Law wrote: > I'm not going to chime in on this specific problem; however, it is worth > noting that many of the issues raised by the C++0x memory model also > affect the linux kernel. But what they are seeing are certainly store data races, not load races, because no hw they care about (or no hw at all?) detects the latter. Having options to avoid store data races is useful not just for C++0x memory model compliance and Linux kernel, but e.g. for OpenMP too. > In fact, it was the realization that the kernel guys are fighting > closely related issues with data races that bumped the priority of the > memory model work to a level that we (Red Hat) felt it was necessary to > start pushing these issues upstream now. Jakub