From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760600AbXGIVAW (ORCPT ); Mon, 9 Jul 2007 17:00:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758821AbXGIVAH (ORCPT ); Mon, 9 Jul 2007 17:00:07 -0400 Received: from dvhart.com ([64.146.134.43]:43675 "EHLO dvhart.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758395AbXGIVAD (ORCPT ); Mon, 9 Jul 2007 17:00:03 -0400 Message-ID: <4692A1D0.50308@mbligh.org> Date: Mon, 09 Jul 2007 14:00:00 -0700 From: Martin Bligh User-Agent: Thunderbird 1.5.0.12 (X11/20070604) MIME-Version: 1.0 To: Christoph Lameter Cc: Andi Kleen , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Mathieu Desnoyers Subject: Re: [patch 00/10] [RFC] SLUB patches for more functionality, performance and maintenance References: <20070708034952.022985379@sgi.com> <46925B5D.8000507@google.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Christoph Lameter wrote: > On Mon, 9 Jul 2007, Martin Bligh wrote: > >> Those numbers came from Mathieu Desnoyers (LTTng) if you >> want more details. > > Okay the source for these numbers is in his paper for the OLS 2006: Volume > 1 page 208-209? I do not see the exact number that you referred to there. Nope, he was a direct co-author on the paper, was working here, and measured it. > He seems to be comparing spinlock acquire / release vs. cmpxchg. So I > guess you got your material from somewhere else? > > Also the cmpxchg used there is the lockless variant. cmpxchg 29 cycles w/o > lock prefix and 112 with lock prefix. > > I see you reference another paper by Desnoyers: > http://tree.celinuxforum.org/CelfPubWiki/ELC2006Presentations?action=AttachFile&do=get&target=celf2006-desnoyers.pdf > > I do not see anything relevant there. Where did those numbers come from? > > The lockless cmpxchg is certainly an interesting idea. Certain for some > platforms I could disable preempt and then do a lockless cmpxchg. Matheiu, can you give some more details? Obviously the exact numbers will vary by archicture, machine size, etc, but it's a good point for discussion. M.