Re: [PATCH 1 of 3 v5/leftover] libxl: enable automatic placement of guests on NUMA nodes [and 1 more messages]

[Juergen Gross <juergen.gross@ts.fujitsu.com>]

Am 18.07.2012 15:40, schrieb Andre Przywara:
> On 07/18/2012 01:00 PM, Ian Jackson wrote:
>> Ian Campbell writes ("Re: [PATCH 1 of 3 v5/leftover] libxl: enable
>> automatic placement of guests on NUMA nodes [and 1 more messages]"):
>>> On Wed, 2012-07-18 at 10:43 +0100, Dario Faggioli wrote:
>>>> What could be done is restricting automatic placement to guests that
>>>> fits on 4 or 8 nodes for 4.2.
>>>
>>> 8 would mean on a 32 node system considering 10,518,300 combinations?
>>>
>>> 4 would mean on a 32 node system considering 35,960 combinations? On a
>>> 64 node system it would mean 635,376 combinations.
>>>
>>> If that's the case then lets go with 4 as the limit for 4.2.0.
>>
>> What is the maximum number of NUMA nodes we might expect to see on a
>> single system in the next five years? I would argue that 32 is too
>> optimistic. 128 or 256 seem like more reasonable upper bounds.
>
> Wow, what are you talking about?
> To calm this down from the AMD side:
> The current Opteron NUMA architecture is limited to exactly 8 nodes.
> This has ever been the case since the release of Opteron and changing
> this is not trivial and will not happen in any near future. In general I
> don't think we will see much bigger NUMA systems, but more cluster like
> architectures.
>
> Maybe Juergen can comment on the Fujitsu side.

I'm not aware of anything with more than 8 nodes. OTOH I'm in the SW
department. I'm not sure I would hear about a larger machine long before
it is announced in public. :-)


Juergen

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Juergen Gross                 Principal Developer Operating Systems
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