bhyve max virtual CPUs

[Peter Grehan]

Hi Allan,

> I asked about increasing it and was told that it can be done by editing
> a value in one of the .h files or something, but the reason it wasn't
> higher was that it didn't scale nicely, and they wanted to reword how it
> works.
>
> I would definitely be interested in this, as we run video transcoding
> (uses a LOT of cpu) on 24 or 32 core machines, and we'd like to pass
> more of the cores into the VM.

  You can bump it by modifying:

sys/amd64/include/vmm.h:#define	VM_MAXCPU	16		/* maximum virtual cpus */

   ... and rebuilding world+kernel.

  Let us know how performance goes with larger values.

  It will probably be a while before this value can be dynamic, but 
that's the goal.

later,

Peter.