Re: [Xen-devel] Ping: c/s 20526 (tools: avoid cpu over-commitment if numa=on)

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

On 13/01/2010 08:15, "Jan Beulich" <JBeulich@xxxxxxxxxx> wrote:

> Andre,
> 
> I'm afraid this change isn't really correct:
> 
>> +                cores_per_node = info['nr_cpus'] / info['nr_nodes']
>> +                nodes_required = (self.info['VCPUs_max'] + cores_per_node -
>> 1) / cores_per_node
> 
> Simply using cores_per_node (as calculated here) as a divisor is bound
> to cause division-by-zero issues, namely when limiting the number of
> CPUs on the Xen command line (maxcpus=). I'm not sure though, what
> a reasonable solution to this might look like, since cores-per-node is
> a meaningless thing in an artificial setup like this, and may also be
> meaningless in asymmetric configurations. So perhaps we really need
> to iterate over nodes while summing up the number of CPUs they
> have until the number of needed vCPU-s was reached.

Yes, please!

 K.



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