Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754380AbZFEDES (ORCPT ); Thu, 4 Jun 2009 23:04:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752281AbZFEDEC (ORCPT ); Thu, 4 Jun 2009 23:04:02 -0400 Received: from e37.co.us.ibm.com ([32.97.110.158]:39219 "EHLO e37.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751721AbZFEDEA (ORCPT ); Thu, 4 Jun 2009 23:04:00 -0400 Date: Fri, 5 Jun 2009 08:33:10 +0530 From: Bharata B Rao To: Avi Kivity Cc: linux-kernel@vger.kernel.org, Dhaval Giani , Balbir Singh , Vaidyanathan Srinivasan , Gautham R Shenoy , Srivatsa Vaddagiri , Ingo Molnar , Peter Zijlstra , Pavel Emelyanov , kvm@vger.kernel.org, Linux Containers , Herbert Poetzl Subject: Re: [RFC] CPU hard limits Message-ID: <20090605030309.GA3872@in.ibm.com> Reply-To: bharata@linux.vnet.ibm.com References: <20090604053649.GA3701@in.ibm.com> <4A27BBCA.5020606@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4A27BBCA.5020606@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1773 Lines: 41 On Thu, Jun 04, 2009 at 03:19:22PM +0300, Avi Kivity wrote: > Bharata B Rao wrote: >> 2. Need for hard limiting CPU resource >> -------------------------------------- >> - Pay-per-use: In enterprise systems that cater to multiple clients/customers >> where a customer demands a certain share of CPU resources and pays only >> that, CPU hard limits will be useful to hard limit the customer's job >> to consume only the specified amount of CPU resource. >> - In container based virtualization environments running multiple containers, >> hard limits will be useful to ensure a container doesn't exceed its >> CPU entitlement. >> - Hard limits can be used to provide guarantees. >> > How can hard limits provide guarantees? > > Let's take an example where I have 1 group that I wish to guarantee a > 20% share of the cpu, and anther 8 groups with no limits or guarantees. > > One way to achieve the guarantee is to hard limit each of the 8 other > groups to 10%; the sum total of the limits is 80%, leaving 20% for the > guarantee group. The downside is the arbitrary limit imposed on the > other groups. This method sounds very similar to the openvz method: http://wiki.openvz.org/Containers/Guarantees_for_resources > > Another way is to place the 8 groups in a container group, and limit > that to 80%. But that doesn't work if I want to provide guarantees to > several groups. Hmm why not ? Reduce the guarantee of the container group and provide the same to additional groups ? Regards, Bharata. -- 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/