From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [RFC] CPU hard limits Date: Fri, 05 Jun 2009 08:21:43 +0300 Message-ID: <4A28AB67.7040800@redhat.com> References: <20090604053649.GA3701@in.ibm.com> <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> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: bharata@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: balbir@linux.vnet.ibm.com Return-path: Received: from mx2.redhat.com ([66.187.237.31]:59566 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750745AbZFEFXT (ORCPT ); Fri, 5 Jun 2009 01:23:19 -0400 In-Reply-To: <20090605051050.GB11755@balbir.in.ibm.com> Sender: kvm-owner@vger.kernel.org List-ID: Balbir Singh wrote: >> But then there is no other way to make a *guarantee*, guarantees come >> at a cost of idling resources, no? Can you show me any other >> combination that will provide the guarantee and without idling the >> system for the specified guarantees? >> > > OK, I see part of your concern, but I think we could do some > optimizations during design. For example if all groups have reached > their hard-limit and the system is idle, should we do start a new hard > limit interval and restart, so that idleness can be removed. Would > that be an acceptable design point? I think so. Given guarantees G1..Gn (0 <= Gi <= 1; sum(Gi) <= 1), and a cpu hog running in each group, how would the algorithm divide resources? -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.