From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752084Ab2BTIOh (ORCPT ); Mon, 20 Feb 2012 03:14:37 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:38255 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751184Ab2BTIOg (ORCPT ); Mon, 20 Feb 2012 03:14:36 -0500 Date: Mon, 20 Feb 2012 09:14:16 +0100 From: Ingo Molnar To: Nikunj A Dadhania Cc: Avi Kivity , Peter Zijlstra , Rik van Riel , linux-kernel@vger.kernel.org, vatsa@linux.vnet.ibm.com, bharata@linux.vnet.ibm.com Subject: Re: [RFC PATCH 0/4] Gang scheduling in CFS Message-ID: <20120220081416.GE30810@elte.hu> References: <87pqf5mqg4.fsf@abhimanyu.in.ibm.com> <4F017AD2.3090504@redhat.com> <87mxa3zqm1.fsf@abhimanyu.in.ibm.com> <4F046536.5080207@redhat.com> <4F048295.1050907@redhat.com> <4F04898B.1080600@redhat.com> <1325712710.3084.10.camel@laptop> <4F04C789.40209@redhat.com> <20120105091059.GA3249@elte.hu> <87fwe6ork3.fsf@abhimanyu.in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87fwe6ork3.fsf@abhimanyu.in.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=AWL,BAYES_00 autolearn=no SpamAssassin version=3.3.1 -2.0 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] 0.0 AWL AWL: From: address is in the auto white-list Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Nikunj A Dadhania wrote: > > Here it would massively improve performance - without > > regressing the scheduler code massively. > > I tried doing an experiment with the flush_tlb_others_ipi. > This depends on Raghu's "kvm : Paravirt-spinlock support for > KVM guests" (https://lkml.org/lkml/2012/1/14/66), which has > new hypercall for kicking another vcpu out of halt. > > Here are the results from non-PLE hardware. Running ebizzy > workload inside the VMs. The table shows the ebizzy score - > Records/sec. > > 8CPU Intel Xeon, HT disabled, 64 bit VM(8vcpu, 1G RAM) > > +--------+------------+------------+-------------+ > | | baseline | gang | pv_flush | > +--------+------------+------------+-------------+ > | 2VM | 3979.50 | 8818.00 | 11002.50 | > | 4VM | 1817.50 | 6236.50 | 6196.75 | > | 8VM | 922.12 | 4043.00 | 4001.38 | > +--------+------------+------------+-------------+ Very nice results! Seems like the PV approach is massively faster on 2 VMs than even the gang scheduling hack, because it attacks the problem at its root, not just the symptom. The patch is also an order of magnitude simpler. Gang scheduling, R.I.P. Thanks, Ingo