From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: Re: PV-vNUMA issue: topology is misinterpreted by the guest Date: Mon, 27 Jul 2015 17:33:59 +0100 Message-ID: <55B65D77.1050202@citrix.com> References: <1437042762.28251.18.camel@citrix.com> <55B64A8A.7040200@citrix.com> <1438012950.5036.215.camel@citrix.com> <55B65CD6.7000607@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta5.messagelabs.com ([195.245.231.135]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1ZJlM0-0003vT-1v for xen-devel@lists.xenproject.org; Mon, 27 Jul 2015 16:34:16 +0000 In-Reply-To: <55B65CD6.7000607@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: David Vrabel , Dario Faggioli Cc: Elena Ufimtseva , Wei Liu , Jan Beulich , "xen-devel@lists.xenproject.org" , Boris Ostrovsky List-Id: xen-devel@lists.xenproject.org On 27/07/15 17:31, David Vrabel wrote: > >>> 2. For HVM guests, use the existing hardware interfaces to present NUMA >>> topology. i.e., CPUID, ACPI tables etc. This will work for both kernel >>> and userspace and both will see the same topology. >>> >>> This also has the advantage that any hypervisor/toolstack work will also >>> be applicable to other guests (e.g., Windows). >>> >> Yeah, indeed. That's the downside of Juergen's "Linux scheduler >> approach". But the issue is there, even without taking vNUMA into >> account, and I think something like that would really help (only for >> Dom0, and Linux guests, of course). > I disagree. Whether we're using vNUMA or not, Xen should still ensure > that the guest kernel and userspace see a consistent and correct > topology using the native mechanisms. +1 ~Andrew