Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754903Ab2ENHim (ORCPT ); Mon, 14 May 2012 03:38:42 -0400 Received: from claw.goop.org ([74.207.240.146]:34456 "EHLO claw.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754483Ab2ENHig (ORCPT ); Mon, 14 May 2012 03:38:36 -0400 Message-ID: <4FB0B679.1020600@goop.org> Date: Mon, 14 May 2012 00:38:33 -0700 From: Jeremy Fitzhardinge User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:12.0) Gecko/20120430 Thunderbird/12.0.1 MIME-Version: 1.0 To: Raghavendra K T CC: Avi Kivity , Srivatsa Vaddagiri , Ingo Molnar , Linus Torvalds , Andrew Morton , Greg Kroah-Hartman , Konrad Rzeszutek Wilk , "H. Peter Anvin" , Marcelo Tosatti , X86 , Gleb Natapov , Ingo Molnar , Attilio Rao , Virtualization , Xen Devel , linux-doc@vger.kernel.org, KVM , Andi Kleen , Stefano Stabellini , Stephan Diestelhorst , LKML , Peter Zijlstra , Thomas Gleixner , "Nikunj A. Dadhania" Subject: Re: [PATCH RFC V8 0/17] Paravirtualized ticket spinlocks References: <20120502100610.13206.40.sendpatchset@codeblue.in.ibm.com> <20120507082928.GI16608@gmail.com> <4FA7888F.80505@redhat.com> <4FA7AAD8.6050003@linux.vnet.ibm.com> <4FA7BABA.4040700@redhat.com> <4FA7CC05.50808@linux.vnet.ibm.com> <4FA7CCA2.4030408@redhat.com> <4FA7D06B.60005@linux.vnet.ibm.com> <20120507134611.GB5533@linux.vnet.ibm.com> <4FA7D2E5.1020607@redhat.com> <4FA7D3F7.9080005@linux.vnet.ibm.com> <4FA7D50D.1020209@redhat.com> <4FA7E06E.20304@linux.vnet.ibm.com> <4FA7E1C8.7010509@redhat.com> <4FB0014A.90604@linux.vnet.ibm.com> In-Reply-To: <4FB0014A.90604@linux.vnet.ibm.com> X-Enigmail-Version: 1.4.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2505 Lines: 66 On 05/13/2012 11:45 AM, Raghavendra K T wrote: > On 05/07/2012 08:22 PM, Avi Kivity wrote: > > I could not come with pv-flush results (also Nikunj had clarified that > the result was on NOn PLE > >> I'd like to see those numbers, then. >> >> Ingo, please hold on the kvm-specific patches, meanwhile. >> > > 3 guests 8GB RAM, 1 used for kernbench > (kernbench -f -H -M -o 20) other for cpuhog (shell script with while > true do hackbench) > > 1x: no hogs > 2x: 8hogs in one guest > 3x: 8hogs each in two guest > > kernbench on PLE: > Machine : IBM xSeries with Intel(R) Xeon(R) X7560 2.27GHz CPU with 32 > core, with 8 online cpus and 4*64GB RAM. > > The average is taken over 4 iterations with 3 run each (4*3=12). and > stdev is calculated over mean reported in each run. > > > A): 8 vcpu guest > > BASE BASE+patch %improvement w.r.t > mean (sd) mean (sd) > patched kernel time > case 1*1x: 61.7075 (1.17872) 60.93 (1.475625) 1.27605 > case 1*2x: 107.2125 (1.3821349) 97.506675 (1.3461878) 9.95401 > case 1*3x: 144.3515 (1.8203927) 138.9525 (0.58309319) 3.8855 > > > B): 16 vcpu guest > BASE BASE+patch %improvement w.r.t > mean (sd) mean (sd) > patched kernel time > case 2*1x: 70.524 (1.5941395) 69.68866 (1.9392529) 1.19867 > case 2*2x: 133.0738 (1.4558653) 124.8568 (1.4544986) 6.58114 > case 2*3x: 206.0094 (1.3437359) 181.4712 (2.9134116) 13.5218 > > B): 32 vcpu guest > BASE BASE+patch %improvementw.r.t > mean (sd) mean (sd) > patched kernel time > case 4*1x: 100.61046 (2.7603485) 85.48734 (2.6035035) 17.6905 What does the "4*1x" notation mean? Do these workloads have overcommit of the PCPU resources? When I measured it, even quite small amounts of overcommit lead to large performance drops with non-pv ticket locks (on the order of 10% improvements when there were 5 busy VCPUs on a 4 cpu system). I never tested it on larger machines, but I guess that represents around 25% overcommit, or 40 busy VCPUs on a 32-PCPU system. J -- 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/