Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762436AbZAORow (ORCPT ); Thu, 15 Jan 2009 12:44:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757667AbZAORoo (ORCPT ); Thu, 15 Jan 2009 12:44:44 -0500 Received: from palinux.external.hp.com ([192.25.206.14]:59411 "EHLO mail.parisc-linux.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755805AbZAORom (ORCPT ); Thu, 15 Jan 2009 12:44:42 -0500 Date: Thu, 15 Jan 2009 10:44:40 -0700 From: Matthew Wilcox To: Ingo Molnar Cc: Linus Torvalds , Peter Zijlstra , "Paul E. McKenney" , Gregory Haskins , Andi Kleen , Chris Mason , Andrew Morton , Linux Kernel Mailing List , linux-fsdevel , linux-btrfs , Thomas Gleixner , Nick Piggin , Peter Morreale , Sven Dietrich , Dmitry Adamushko , Johannes Weiner Subject: Re: [GIT PULL] adaptive spinning mutexes Message-ID: <20090115174440.GF29283@parisc-linux.org> References: <1231859742.442.128.camel@twins> <1231863710.7141.3.camel@twins> <1231864854.7141.8.camel@twins> <1231867314.7141.16.camel@twins> <1231952436.14825.28.camel@laptop> <20090114183319.GA18630@elte.hu> <20090114184746.GA21334@elte.hu> <20090114192811.GA19691@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090114192811.GA19691@elte.hu> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1503 Lines: 33 On Wed, Jan 14, 2009 at 08:28:11PM +0100, Ingo Molnar wrote: > [v2.6.14] [v2.6.29] > > Semaphores | Mutexes > ---------------------------------------------- > | no-spin spin > | > [tmpfs] ops/sec: 50713 | 291038 392865 (+34.9%) > [ext3] ops/sec: 45214 | 283291 435674 (+53.7%) > > A 10x macro-performance improvement on ext3, compared to 2.6.14 :-) > > While lots of other details got changed meanwhile, i'm sure most of the > performance win on this particular VFS workload comes from mutexes. I asked a couple of our benchmarking teams to try -v9. Neither the OLTP benchmark, nor the kernel-perf test suite found any significant performance change. I suspect mutex contention isn't a significant problem for most workloads. Has anyone found a non-synthetic benchmark where this makes a significant difference? Aside from btrfs, I mean. -- Matthew Wilcox Intel Open Source Technology Centre "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step." -- 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/