From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932749AbXH0UTz (ORCPT ); Mon, 27 Aug 2007 16:19:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932119AbXH0UTq (ORCPT ); Mon, 27 Aug 2007 16:19:46 -0400 Received: from tomts5-srv.bellnexxia.net ([209.226.175.25]:64340 "EHLO tomts5-srv.bellnexxia.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758728AbXH0UTp (ORCPT ); Mon, 27 Aug 2007 16:19:45 -0400 Date: Mon, 27 Aug 2007 16:19:41 -0400 From: Mathieu Desnoyers To: Christoph Lameter Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [patch 00/28] Add cmpxchg64_local and cmpxchg_local to each architecture Message-ID: <20070827201941.GA5653@Krystal> References: <20070827155234.062715780@polymtl.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline In-Reply-To: X-Editor: vi X-Info: http://krystal.dyndns.org:8080 X-Operating-System: Linux/2.6.21.3-grsec (i686) X-Uptime: 16:12:09 up 28 days, 20:31, 4 users, load average: 0.64, 0.34, 0.33 User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Christoph Lameter (clameter@sgi.com) wrote: > On Mon, 27 Aug 2007, Mathieu Desnoyers wrote: > > > Here is the patch series for 2.6.23-rc3-mm1 that adds cmpxchg_local, and now > > also cmpxchg64_local, to each architecture. > > Any planned uses of cmpxchg64_local? Let's say it could possibly eliminate the xtime read seqlock on x86 (should be investigated) and can be useful to overcome the non-synchronized TSC handling when taking TSC-based timestamps. All these operations require locking to play with 64 bits values on 32 bits architectures, which could be improved by cmpxchg64_local. But again, it would require some testing to see if we can improve performances there. Mathieu -- Mathieu Desnoyers Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68