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Re: [Xen-devel] Xen 3.4.1 NUMA support

To: Jan Beulich <JBeulich@xxxxxxxxxx>, Andre Przywara <andre.przywara@xxxxxxx>, Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>
Subject: Re: [Xen-devel] Xen 3.4.1 NUMA support
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Thu, 12 Nov 2009 16:09:55 +0000
Cc: George Dunlap <George.Dunlap@xxxxxxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, Papagiannis Anastasios <apapag@xxxxxxxxxxxx>
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On 09/11/2009 15:19, "Jan Beulich" <JBeulich@xxxxxxxxxx> wrote:

>>>> Andre Przywara <andre.przywara@xxxxxxx> 09.11.09 16:02 >>>
>> BTW: Shouldn't we set finally numa=on as the default value?
> I'd say no, at least until the default confinement of a guest to a single
> node gets fixed to properly deal with guests having more vCPU-s than
> a node's worth of pCPU-s (i.e. I take it for granted that the benefits of
> not overcommitting CPUs outweigh the drawbacks of cross-node memory
> accesses at the very least for CPU-bound workloads).

If this would be fixed (e.g., turn off node locality entirely by default for
domains which will not fit into a single node) then I think we could
consider numa=on by default.

 -- Keir

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