From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Subject: Re: [PATCH 0/3 v2] mutex: Improve mutex performance by doing less atomic-ops & better spinning Date: Tue, 16 Apr 2013 11:12:59 +0200 Message-ID: <20130416091259.GC9569@gmail.com> References: <1366036679-9702-1-git-send-email-Waiman.Long@hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1366036679-9702-1-git-send-email-Waiman.Long@hp.com> Sender: linux-kernel-owner@vger.kernel.org To: Waiman Long Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , "Paul E. McKenney" , David Howells , Dave Jones , Clark Williams , Peter Zijlstra , linux-kernel@vger.kernel.org, x86@kernel.org, linux-arch@vger.kernel.org, "Chandramouleeswaran, Aswin" , Davidlohr Bueso , "Norton, Scott J" , Rik van Riel List-Id: linux-arch.vger.kernel.org * Waiman Long wrote: > [...] > > Patches 2 improves the mutex spinning process by reducing contention among the > spinners when competing for the mutex. This is done by using a MCS lock to put > the spinners in a queue so that only the first spinner will try to acquire the > mutex when it is available. This patch showed significant performance > improvement of +30% on the AIM7 fserver and new_fserver workload. Ok, that's really nice - and this approach has no arbitrary limits/tunings in it. Do you have a performance comparison to your first series (patches 1+2+3 IIRC) - how does this new series with MCS locking compare to the best previous result from that old series? Do we now achieve that level of performance? Thanks, Ingo From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ee0-f51.google.com ([74.125.83.51]:54151 "EHLO mail-ee0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755354Ab3DPJNE (ORCPT ); Tue, 16 Apr 2013 05:13:04 -0400 Date: Tue, 16 Apr 2013 11:12:59 +0200 From: Ingo Molnar Subject: Re: [PATCH 0/3 v2] mutex: Improve mutex performance by doing less atomic-ops & better spinning Message-ID: <20130416091259.GC9569@gmail.com> References: <1366036679-9702-1-git-send-email-Waiman.Long@hp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1366036679-9702-1-git-send-email-Waiman.Long@hp.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Waiman Long Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , "Paul E. McKenney" , David Howells , Dave Jones , Clark Williams , Peter Zijlstra , linux-kernel@vger.kernel.org, x86@kernel.org, linux-arch@vger.kernel.org, "Chandramouleeswaran, Aswin" , Davidlohr Bueso , "Norton, Scott J" , Rik van Riel Message-ID: <20130416091259.z-5zxvgpS2T6DRwiCG7tsnltxyJ2IhBGQk6az8r4yHw@z> * Waiman Long wrote: > [...] > > Patches 2 improves the mutex spinning process by reducing contention among the > spinners when competing for the mutex. This is done by using a MCS lock to put > the spinners in a queue so that only the first spinner will try to acquire the > mutex when it is available. This patch showed significant performance > improvement of +30% on the AIM7 fserver and new_fserver workload. Ok, that's really nice - and this approach has no arbitrary limits/tunings in it. Do you have a performance comparison to your first series (patches 1+2+3 IIRC) - how does this new series with MCS locking compare to the best previous result from that old series? Do we now achieve that level of performance? Thanks, Ingo