From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 18674 invoked by alias); 18 Aug 2013 20:29:37 -0000 Mailing-List: contact libc-ports-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: libc-ports-owner@sourceware.org Received: (qmail 18660 invoked by uid 89); 18 Aug 2013 20:29:37 -0000 X-Spam-SWARE-Status: No, score=-4.7 required=5.0 tests=AWL,BAYES_00,KHOP_RCVD_UNTRUST,KHOP_THREADED,RCVD_IN_HOSTKARMA_W,RCVD_IN_HOSTKARMA_WL autolearn=ham version=3.3.2 Received: from relay1.mentorg.com (HELO relay1.mentorg.com) (192.94.38.131) by sourceware.org (qpsmtpd/0.84/v0.84-167-ge50287c) with ESMTP; Sun, 18 Aug 2013 20:29:36 +0000 Received: from svr-orw-exc-10.mgc.mentorg.com ([147.34.98.58]) by relay1.mentorg.com with esmtp id 1VB9bS-0004V0-WC from joseph_myers@mentor.com ; Sun, 18 Aug 2013 13:29:35 -0700 Received: from SVR-IES-FEM-01.mgc.mentorg.com ([137.202.0.104]) by SVR-ORW-EXC-10.mgc.mentorg.com with Microsoft SMTPSVC(6.0.3790.4675); Sun, 18 Aug 2013 13:29:35 -0700 Received: from digraph.polyomino.org.uk (137.202.0.76) by SVR-IES-FEM-01.mgc.mentorg.com (137.202.0.104) with Microsoft SMTP Server id 14.2.247.3; Sun, 18 Aug 2013 21:29:33 +0100 Received: from jsm28 (helo=localhost) by digraph.polyomino.org.uk with local-esmtp (Exim 4.76) (envelope-from ) id 1VB9bQ-0006eI-8i; Sun, 18 Aug 2013 20:29:32 +0000 Date: Sun, 18 Aug 2013 20:29:00 -0000 From: "Joseph S. Myers" To: Dinar Temirbulatov CC: , Subject: Re: [Patch] ARM define atomic_exchange_acq/atomic_exchange_rel to __atomic_exchange_n In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" X-SW-Source: 2013-08/txt/msg00011.txt.bz2 On Tue, 13 Aug 2013, Dinar Temirbulatov wrote: > Hello, > Following patch redefines atomic_exchange_acq/atomic_exchange_rel to > __atomic_exchange_n for ARM, that allows for example to reduce number > of instruction sequence for lll_unlock > from: > ldex, cmp, bne, stex, cmp, bne > to > ldex, stex, cmp, bne > , more on the issue here: > http://sourceware.org/bugzilla/show_bug.cgi?id=15640 > > This patch was tested on ARM a9 with glibc testsuite with no new > regressions. OK to commit? What does this do when building for an ARM architecture version where the kernel helpers need to be used for atomicity? I think what's desired in such a case is for the operations to continue to be expanded with inline calls to the kernel helpers. Generating out-of-line calls to libgcc helpers would be less desirable (and out-of-line calls to anything not in libgcc.a would break the build). -- Joseph S. Myers joseph@codesourcery.com