From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762984AbXGJUw4 (ORCPT ); Tue, 10 Jul 2007 16:52:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757554AbXGJUws (ORCPT ); Tue, 10 Jul 2007 16:52:48 -0400 Received: from netops-testserver-4-out.sgi.com ([192.48.171.29]:46387 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1758118AbXGJUwr (ORCPT ); Tue, 10 Jul 2007 16:52:47 -0400 Date: Tue, 10 Jul 2007 13:52:47 -0700 (PDT) From: Christoph Lameter X-X-Sender: clameter@schroedinger.engr.sgi.com To: Andi Kleen cc: Nick Piggin , Linus Torvalds , Linux Kernel Mailing List Subject: Re: queued spinlock code and results In-Reply-To: Message-ID: References: <20070708043228.GB22397@wotan.suse.de> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 8 Jul 2007, Andi Kleen wrote: > I would say the main drawback of switchable and queued locks > would be also that they require a larger spinlock_t thus increasing > cache usage Right. Zoran Radovic has shown that queued locks are inferior to other approaches. The best approach that he found in his research were the HBO locks that are somewhat more intelligent form of spinlocks. http://user.it.uu.se/~zoranr/ http://www.it.uu.se/research/group/uart/projects/nucasynch/ Paper on the issue with measurements: http://www.it.uu.se/research/publications/lic/2003-008/2003-008.pdf