From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [RFC] CPU hard limits Date: Fri, 05 Jun 2009 15:57:54 +0300 Message-ID: <4A291652.4090308@redhat.com> References: <4A27BBCA.5020606@redhat.com> <20090605030309.GA3872@in.ibm.com> <4A28921C.6010802@redhat.com> <661de9470906042137u603e2997n80c270bf7f6191ad@mail.gmail.com> <4A28A2AB.3060108@redhat.com> <20090605044946.GA11755@balbir.in.ibm.com> <20090605051050.GB11755@balbir.in.ibm.com> <4A28AB67.7040800@redhat.com> <20090605052755.GE11755@balbir.in.ibm.com> <4A28B539.3050001@redhat.com> <20090605063243.GC3872@in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: balbir@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, Dhaval Giani , Vaidyanathan Srinivasan , Gautham R Shenoy , Srivatsa Vaddagiri , Ingo Molnar , Peter Zijlstra , Pavel Emelyanov , kvm@vger.kernel.org, Linux Containers , Herbert Poetzl To: bharata@linux.vnet.ibm.com Return-path: Received: from mx2.redhat.com ([66.187.237.31]:56975 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751368AbZFEM7i (ORCPT ); Fri, 5 Jun 2009 08:59:38 -0400 In-Reply-To: <20090605063243.GC3872@in.ibm.com> Sender: kvm-owner@vger.kernel.org List-ID: Bharata B Rao wrote: >> So the groups with guarantees get a priority boost. That's not a good >> side effect. >> > > That happens only in the presence of idle cycles when other groups [with or > without guarantees] have nothing useful to do. So how would that matter > since there is nothing else to run anyway ? > If there are three groups, each running a cpu hog, and they have (say) guarantees of 10%, 10%, and 0%, then they should each get 33% of the cpu, not biased towards the groups with the guarantee. If I want to change the weights, I'll alter their priority. -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.