On Thu, Jan 24, 2008 at 07:45:34AM +0900, Curt Sampson wrote:
> 
> As well, since I'm on the topic, I understand that NetBSD 4 doesn't
> have any support for multiprocessing under xen. My domUs have one CPU
> allocated according to xm top, and the dmesg shows a single vcpu, as
> expected. However, my dom0 has two CPUs allocated, according to xm top,
> and the dmesg, though it shows one vcpu, also shows before that:
> 
>     cpu0 at mainbus0: apid 0 (boot processor)
>     cpu1 at mainbus0: apid 1 (application processor)
> 
> What's the meaning of this?

`xm top' shows what the hypervisor sees and I think top(1) should be the
reference for the number of cpus seen by dom0. On my netbsd-4/Xen3 dom0
(running on a dual-core Athlon64) `xm top' reports two, top(1) just one
cpu.

The following thread has some additional information on this topic:

http://archive.netbsd.se/?ml=port-xen&a=2006-03&t=1887649