Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756774AbaGVTgV (ORCPT ); Tue, 22 Jul 2014 15:36:21 -0400 Received: from g4t3427.houston.hp.com ([15.201.208.55]:16160 "EHLO g4t3427.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756535AbaGVTgT (ORCPT ); Tue, 22 Jul 2014 15:36:19 -0400 Message-ID: <53CEBD2F.2040705@hp.com> Date: Tue, 22 Jul 2014 15:36:15 -0400 From: Waiman Long User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:10.0.12) Gecko/20130109 Thunderbird/10.0.12 MIME-Version: 1.0 To: Ingo Molnar CC: Thomas Gleixner , Peter Zijlstra , Darren Hart , Davidlohr Bueso , Heiko Carstens , linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, linux-doc@vger.kernel.org, Jason Low , Scott J Norton Subject: Re: [RFC PATCH 0/5] futex: introduce an optimistic spinning futex References: <1405956271-34339-1-git-send-email-Waiman.Long@hp.com> <20140721211801.GA12149@gmail.com> In-Reply-To: <20140721211801.GA12149@gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/21/2014 05:18 PM, Ingo Molnar wrote: > * Waiman Long wrote: > >> Testing done on a 4-socket Westmere-EX boxes with 40 cores (HT off) >> showed the following performance data (average kops/s) with various >> load factor (number of pause instructions) used in the critical >> section using an userspace mutex microbenchmark. >> >> Threads Load Waiting Futex Spinning Futex %Change >> ------- ---- ------------- -------------- ------- >> 256 1 6894 8883 +29% >> 256 10 3656 4912 +34% >> 256 50 1332 4358 +227% >> 256 100 792 2753 +248% >> 10 1 6382 4838 -24% >> 10 10 3614 4748 +31% >> 10 50 1319 3900 +196% >> 10 100 782 2459 +214% >> 2 1 7905 7194 -9.0% >> 2 10 4556 4717 +3.5% >> 2 50 2191 4167 +90% >> 2 100 1767 2407 +36% > So the numbers look interesting - but it would be _really_ important > to provide noise/sttdev figures in a sixth column as well (denoted in > percentage units, not in benchmark units), so that we know how > significant a particular speedup (or slowdown) is. > > Thanks, > > Ingo The performance can varies quite a bit depending on what other processes are running at the test execution time. I will include stddev data in the next iteration of the patch. -Longman -- 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/