From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jes Sorensen Subject: Re: [PATCH 0/3][RFC] NUMA: add host side pinning Date: Fri, 25 Jun 2010 13:37:09 +0200 Message-ID: <4C2494E5.50409@redhat.com> References: <1277327377-29629-1-git-send-email-andre.przywara@amd.com> <4C2288DD.3020207@codemonkey.ws> <865764AB-4E51-4ED4-8832-AED6A237A9D3@suse.de> <4C233A6D.7030805@amd.com> <4C233DAB.60106@redhat.com> <4C2342D1.4090103@amd.com> <4C248C55.9020204@redhat.com> <4C248D9C.8040108@amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Avi Kivity , Alexander Graf , Anthony Liguori , "kvm@vger.kernel.org" To: Andre Przywara Return-path: Received: from mx1.redhat.com ([209.132.183.28]:5358 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751624Ab0FYLhS (ORCPT ); Fri, 25 Jun 2010 07:37:18 -0400 In-Reply-To: <4C248D9C.8040108@amd.com> Sender: kvm-owner@vger.kernel.org List-ID: On 06/25/10 13:06, Andre Przywara wrote: > Jes Sorensen wrote: >> On 06/24/10 13:34, Andre Przywara wrote: >> I really think it makes more sense to make QEMU aware of the NUMA setup >> as well, rather than relying on numctl to do the work outside. >> >> One thing you need to consider is what happens with migration once a >> user specifies -numa. IMHO it is acceptable to simply disable migration >> for the given guest. > Is that really a problem? You create the guest on the target with a NUMA > setup specific to the target machine. That could mean that you pin > multiple guest nodes to the same host node, but that shouldn't break > something, right? The guest part can (and should be!) migrated along > with all the other device state. I think this is still missing from the > current implementation. It may be hard to guarantee the memory layout on the target machine it may have a completely different topology. The numa bindings ought to go into the state and be checked against the target machine's state, but for instance you could be trying to bind things to node 7-8 on the first host while migration target only has 2 nodes, but plenty of memory. Or you use mode nodes on the first host than you have on the second. It's a very complicated matrix to try and match. >> PS: Are you planning on submitting anything to Linux Plumbers Conference >> about this? :) > Yes, I was planning to submit a proposal, as I saw NUMA mentioned in the > topics list. AFAIK the deadline is July 19th, right? That gives me > another week after my vacation (for which I leave in a few minutes). Excellent! yes it should still by July 19th. Enjoy your vacation! Jes