How hard is BHyVe's 16 vCPU limit, is it configurable under any circumstance?

[Allan Jude]

On 2014-11-12 16:39, tinkr at openmailbox.org wrote:
> Hi!
> 
> In order justify giving energy to BHyVe, I need to know if it's
> "future-proof" in that the 16 vCPU limit can be increased?
> 
> Please let the world know if BHyVe's 16 vCPU limit can be lifted in some
> way, by configuration, patch, etc. (and if you want to, why this limit
> is in place by default today).
> 
> Thanks!!
> Tinker
> 
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You can increase the limit by editing sys/amd64/include/vmm.h

#define VM_MAXCPU       16

From what I've been told, things scale badly above 24 CPUs. They plan to
solve this issue, but have not yet. If you system has enough cores to
support using more than 16 per VM, you can modify the file and recompile
the kernel and use as many CPUs as you want, but not much testing has
happened with bigger numbers.

-- 
Allan Jude

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