Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757928AbXKCDl5 (ORCPT ); Fri, 2 Nov 2007 23:41:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756792AbXKCDlv (ORCPT ); Fri, 2 Nov 2007 23:41:51 -0400 Received: from mx2.suse.de ([195.135.220.15]:44994 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756772AbXKCDlu (ORCPT ); Fri, 2 Nov 2007 23:41:50 -0400 Date: Sat, 3 Nov 2007 04:41:46 +0100 From: Nick Piggin To: Chuck Ebbert Cc: Linus Torvalds , Linux Kernel Mailing List , Andi Kleen , Ingo Molnar Subject: Re: [patch 1/4] x86: FIFO ticket spinlocks Message-ID: <20071103034146.GA9699@wotan.suse.de> References: <20071101140146.GA26879@wotan.suse.de> <20071101140320.GC26879@wotan.suse.de> <472B4ECE.7010602@redhat.com> <20071102230142.GC26562@wotan.suse.de> <472BC74E.9090505@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <472BC74E.9090505@redhat.com> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 725 Lines: 18 On Fri, Nov 02, 2007 at 08:56:46PM -0400, Chuck Ebbert wrote: > On 11/02/2007 07:01 PM, Nick Piggin wrote: > > > > In the contended multi-threaded tight loop, the xchg lock is slower than inc > > lock but still beats the fair xadd lock, but that's only because it is > > just as unfair if not more so on this hardware (runtime difference of up to > > about 10%) > > > > I meant xchg for unlock, not lock. That is for unlock. 2x the number of atomic operations ~= 2x the cost. - 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/