From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751099AbWFRGL0 (ORCPT ); Sun, 18 Jun 2006 02:11:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751100AbWFRGL0 (ORCPT ); Sun, 18 Jun 2006 02:11:26 -0400 Received: from smtp107.mail.mud.yahoo.com ([209.191.85.217]:16997 "HELO smtp107.mail.mud.yahoo.com") by vger.kernel.org with SMTP id S1751099AbWFRGLZ (ORCPT ); Sun, 18 Jun 2006 02:11:25 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com.au; h=Received:Message-ID:Date:From:User-Agent:X-Accept-Language:MIME-Version:To:CC:Subject:References:In-Reply-To:Content-Type:Content-Transfer-Encoding; b=jY/MdpcXhsvH4YXPppH0ZTdQUgn/FVULAbYSxUMs6aD1lHusJfSMKZzzRxjtgPx8ns+iWWxEWhf5RhIPppvbf6j47x9x+rUnQE4sqqQoHyrrEXEBkyyiFV3WLNEMGg/PDbBJoXNdkL6/QZ36oo+sZka5nN0lpkHX1exSxvV8sfg= ; Message-ID: <4494EE86.7090209@yahoo.com.au> Date: Sun, 18 Jun 2006 16:11:18 +1000 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.12) Gecko/20051007 Debian/1.7.12-1 X-Accept-Language: en MIME-Version: 1.0 To: Sam Vilain CC: vatsa@in.ibm.com, Kirill Korotaev , Mike Galbraith , Ingo Molnar , Peter Williams , Andrew Morton , sekharan@us.ibm.com, Balbir Singh , linux-kernel@vger.kernel.org, maeda.naoaki@jp.fujitsu.com, kurosawa@valinux.co.jp Subject: Re: [RFC] CPU controllers? References: <20060615134632.GA22033@in.ibm.com> <4493C1D1.4020801@yahoo.com.au> <20060617164812.GB4643@in.ibm.com> <4494DF50.2070509@yahoo.com.au> <4494EA66.8030305@vilain.net> In-Reply-To: <4494EA66.8030305@vilain.net> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Sam Vilain wrote: > Nick Piggin wrote: > >>> I think a proportional-share scheduler (which is what a CPU controller >>> may provide) has non-container uses also. Do you think nice (or sched >>> policy) is enough to, say, provide guaranteed CPU usage for >>> applications or limit their CPU usage? Moreover it is more flexible >>> if guarantee/limit can be specified for a group of tasks, rather than >>> individual tasks even in >>> non-container scenarios (like limiting CPU usage of all web-server >>> tasks togther or for limiting CPU usage of make -j command). >>> >> >> Oh, I'm sure there are lots of things we *could* do that we currently >> can't. >> >> What I want to establish first is: what exact functionality is >> required, why, and by whom. > > > You make it sound like users should feel sorry for wanting features > already commonly available on other high performance unix kernels. If telling me what exact functionality they want is going to cause them so much pain, I suppose they should feel sorry for themselves. And I don't care about any other kernels, unix or not. I care about what Linux users want. > > The answer is quite simple, people who are consolidating systems and > working with fewer, larger systems, want to mark processes, groups of > processes or entire containers into CPU scheduling classes, then either > fair balance between them, limit them or reserve them a portion of the > CPU - depending on the user and what their requirements are. What is > unclear about that? > It is unclear whether we should have hard limits, or just nice like priority levels. Whether virtualisation (+/- containers) could be a good solution, etc. If you want to *completely* isolate N groups of users, surely you have to use virtualisation, unless you are willing to isolate memory management, pagecache, slab caches, network and disk IO, etc. > Yes, this does get somewhat simpler if you strap yourself into a > complete virtualisation straightjacket, but the current thread is not > about that approach - and the continual suggestions that we are all just > being stupid and going about it the wrong way are locally off-topic. I'm sorry you cannot come up with a statement of the functionality you require without badmouthing "complete" virtualisation or implying that I'm saying you're stupid. I think the containers people might also recognise that it may not be the best solution to make containers the be all and end all of consolidating systems, and virtualisation is a very relevant topic when discussing pros and cons and alternate solutions. But at this point I'm yet to be shown what the *problem* is. I'm not trying to deny that one might exist. > > Bear in mind that we have on the table at least one group of scheduling > solutions (timeslice scaling based ones, such as the VServer one) which > is virtually no overhead and could potentially provide the "jumpers" > necessary for implementing more complex scheduling policies. Again, I don't care about the solutions at this stage. I want to know what the problem is. Please? -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com