Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761970AbXHTV3g (ORCPT ); Mon, 20 Aug 2007 17:29:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756176AbXHTV3Z (ORCPT ); Mon, 20 Aug 2007 17:29:25 -0400 Received: from tomts5.bellnexxia.net ([209.226.175.25]:61850 "EHLO tomts5-srv.bellnexxia.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751895AbXHTV3Y (ORCPT ); Mon, 20 Aug 2007 17:29:24 -0400 Date: Mon, 20 Aug 2007 17:29:22 -0400 From: Mathieu Desnoyers To: Christoph Lameter Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, mingo@redhat.com Subject: Re: [patch 01/23] Fall back on interrupt disable in cmpxchg8b on 80386 and 80486 Message-ID: <20070820212922.GA27011@Krystal> References: <20070820201519.512791382@polymtl.ca> <20070820201822.597720007@polymtl.ca> <20070820204126.GA22507@Krystal> 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: 17:28:06 up 21 days, 21:46, 4 users, load average: 0.26, 0.36, 0.65 User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1171 Lines: 29 * Christoph Lameter (clameter@sgi.com) wrote: > On Mon, 20 Aug 2007, Mathieu Desnoyers wrote: > > > Yes, I use it as synchronization mechanism for my buffer management algorithm > > in LTTng. Since I write in per-cpu buffers and want to be as reentrant > > as possible wrt other contexts (dealing with NMI as worse case, but also > > applies to MCE..), I use local_cmpxchg to reserve space in my buffers. > > It is faster than the standard cmpxchg. > > Ok I have seen these numbers in the OLS papers but I could not reproduce > them in SLUB. > I'm digging in the slub with cmpxchg_local patch... first detail: slab_alloc seems to have a return path that does not reenable preemption... I'll keep you posted when I finish the 2.6.23-rc2-mm2 port. 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 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/