Re: [Xen-devel] Xen CPU limit?

[Pasi Kärkkäinen <pasik@xxxxxx>]

On Tue, Mar 30, 2010 at 08:16:26AM +0100, Jan Beulich wrote:
> >>> Pasi Kärkkäinen<pasik@xxxxxx> 29.03.10 17:49 >>>
> >I think the number of virtual cpus (vcpus) per guest is (was) 32,
> >and now in Xen 4.0.0 you can have up to 64 vcpus per guest.
> 
> I don't think the tools are up to anything beyond 32 yet. 

Hmm.. what's actually missing from the tools to handle >32 vcpus?

> The (64-bit) hypervisor allows up to 8192 vCPU-s iirc (but that's a truly
> theoretical limit, as Dom0 or a guest likely won't be able to bring up
> that many due to there only being 4096 event channels; current
> Linux requires 5-6 of them per vCPU for IPIs and timer vIRQ).
>

Wow.. I wasn't aware the (theoretical) limit is that big :)

-- Pasi
 

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