Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754749AbZI3Paz (ORCPT ); Wed, 30 Sep 2009 11:30:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754733AbZI3Paz (ORCPT ); Wed, 30 Sep 2009 11:30:55 -0400 Received: from e23smtp01.au.ibm.com ([202.81.31.143]:54767 "EHLO e23smtp01.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754732AbZI3Pay (ORCPT ); Wed, 30 Sep 2009 11:30:54 -0400 Date: Wed, 30 Sep 2009 21:00:53 +0530 From: Balbir Singh To: Pavel Emelyanov Cc: bharata@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, Dhaval Giani , Vaidyanathan Srinivasan , Gautham R Shenoy , Srivatsa Vaddagiri , Ingo Molnar , Peter Zijlstra , Herbert Poetzl , Avi Kivity , Chris Friesen , Paul Menage , Mike Waychison Subject: Re: [RFC v2 PATCH 0/8] CFS Hard limits - v2 Message-ID: <20090930153053.GM3071@balbir.in.ibm.com> Reply-To: balbir@linux.vnet.ibm.com References: <20090930124919.GA19951@in.ibm.com> <4AC35EDD.1080902@openvz.org> <20090930143820.GG3071@balbir.in.ibm.com> <4AC374E3.9000308@openvz.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <4AC374E3.9000308@openvz.org> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1938 Lines: 44 * Pavel Emelyanov [2009-09-30 19:10:27]: > Balbir Singh wrote: > > * Pavel Emelyanov [2009-09-30 17:36:29]: > > > >> Bharata B Rao wrote: > >>> Hi, > >>> > >>> Here is the v2 post of hard limits feature for CFS group scheduler. This > >>> RFC post mainly adds runtime borrowing feature and has a new locking scheme > >>> to protect CFS runtime related fields. > >>> > >>> It would be nice to have some comments on this set! > >> I have a question I'd like to ask before diving into the code. > >> Consider I'm a user, that has a 4CPUs box 2GHz each and I'd like > >> to create a container with 2CPUs 1GHz each. Can I achieve this > >> after your patches? > > > > I don't think the GHz makes any sense, consider CPUs with frequency > > scaling. If I can scale from 1.6GHz to say 2.6GHz or 2GHz to 4GHz, > > what does it mean for hard limit control? Hard limits define control > > over existing bandwidth, anything else would be superficial and hard > > hard to get right for both developers and users. > > Two numbers for configuring limits make even less sense OTOH ;) > By assigning 2GHz for 4GHz CPU I obviously want half of its power ;) > Please, see my reply to vatsa@ in this thread. But it makes life more difficult for the administrator to think in terms of GHz -- no? Specifically with different heterogeneous systems. I think it would be chaotic in a data center to configure GHz for every partition. Not to say that it makes it even more confusing when running on top of KVM. Lets say I create two vCPUs and I specifiy GHz outside, do I expect to see it in /proc/cpuinfo? I'd like to hear what others think about GHz as well. -- Balbir -- 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/