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

[Andre Przywara <andre.przywara@amd.com>]

Jan Beulich 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.
Thanks for the heads-up. I have created a better patch basically doing 
what you described, actually it is even more elegant than the original 
version. I am about to test it and will send it out as soon as the 
testing is finished.

Regards,
Andre.

-- 
Andre Przywara
AMD-Operating System Research Center (OSRC), Dresden, Germany
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