From mboxrd@z Thu Jan 1 00:00:00 1970 From: Juergen Gross Subject: Re: Cpu pools discussion Date: Tue, 28 Jul 2009 15:39:50 +0200 Message-ID: <4A6EFFA6.3000405@ts.fujitsu.com> References: <4A6E492D.201@oracle.com> <20090728091929.GI5235@york.uk.xensource.com> <4A6ECFD3.4030709@ts.fujitsu.com> <20090728130701.GJ5235@york.uk.xensource.com> <4A6EFC11.9010404@ts.fujitsu.com> <20090728133134.GK5235@york.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20090728133134.GK5235@york.uk.xensource.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Tim Deegan Cc: George Dunlap , Zhigang Wang , "xen-devel@lists.xensource.com" , Keir Fraser List-Id: xen-devel@lists.xenproject.org Tim Deegan wrote: > At 14:24 +0100 on 28 Jul (1248791073), Juergen Gross wrote: >>> Does strict partitioning of CPUs like this satisfy everyone's >>> requirements? Bearing in mind that >>> >>> - It's not work-conserving, i.e. it doesn't allow best-effort >>> scheduling of pool A's vCPUs on the idle CPUs of pool B. >>> >>> - It restricts the maximum useful number of vCPUs per guest to the size >>> of a pool rather than the size of the machine. >>> >>> - dom0 would be restricted to a subset of CPUs. That seems OK to me >>> but occasionally people talk about having dom0's vCPUs pinned 1-1 on >>> the physical CPUs. >> You don't have to define other pools. You can just live with the default pool >> extended to all cpus and everything is as today. > > Yep, all I'm saying is you can't do both. If the people who want this > feature (so far I count two of you) want to do both, then this > solution's good not enough, and we should think about that before going > ahead with it. Okay. I think your first point is the most important one. It might be possible to build a load balancing scheme to shift cpus between pools dynamically, but this should be step 2, I think :-) But it would be a nice project :-) Juergen -- Juergen Gross Principal Developer Operating Systems TSP ES&S SWE OS6 Telephone: +49 (0) 89 636 47950 Fujitsu Technolgy Solutions e-mail: juergen.gross@ts.fujitsu.com Otto-Hahn-Ring 6 Internet: ts.fujitsu.com D-81739 Muenchen Company details: ts.fujitsu.com/imprint.html