From mboxrd@z Thu Jan  1 00:00:00 1970
From: Pasi =?iso-8859-1?Q?K=E4rkk=E4inen?= <pasik@iki.fi>
Subject: Re: Xen CPU limit?
Date: Tue, 30 Mar 2010 10:53:06 +0300
Message-ID: <20100330075306.GY1878@reaktio.net>
References: <4B991586.30602@cancer.org.uk> <20100329154901.GE1878@reaktio.net>
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To: Jan Beulich <JBeulich@novell.com>
Cc: xen-devel@lists.xensource.com, Martin Lukasik <martin.lukasik@cancer.org.uk>
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On Tue, Mar 30, 2010 at 08:16:26AM +0100, Jan Beulich wrote:
> >>> Pasi K=E4rkk=E4inen<pasik@iki.fi> 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.
>=20
> I don't think the tools are up to anything beyond 32 yet.=20

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 tru=
ly
> 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
=20