Subject: Re: SMP and Xen
To: Steven M. Bellovin <firstname.lastname@example.org>
From: Manuel Bouyer <email@example.com>
Date: 01/03/2007 13:56:47
On Tue, Jan 02, 2007 at 10:52:43AM -0500, Steven M. Bellovin wrote:
> I have a dual-processor machine I'm using for Xen. A few questions...
> First -- is it safe to use SMP with Xen? I've heard contradictory
> opinions on this. This is Xen3.0.3 on 4.0beta2.
I have a server here with 2 hyperthreaded dual-core intel CPUs. Xen sees
8 CPUs, and runs fine
> Second -- should my Dom0 see both CPUs? Currently, it does not.
It will see all physical cpus (cpu0, cpu1, etc ...) but only one vcpu for
> Third -- is there any performance benefit to setting 'vcpus' to 2 (for
> a DomU that would benefit from that)? That is, will a DomU actually
> run on more than one CPU?
A linux domU will (I have one with 8 vcpus on the abobe server), a NetBSD
domU won't for now. Adding SMP surport to NetBSD/Xen is on my todo list, but
it will take some time ...
Manuel Bouyer, LIP6, Universite Paris VI. Manuel.Bouyer@lip6.fr
NetBSD: 26 ans d'experience feront toujours la difference