This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


Re: [Xen-users] XenServer adding additional CPUs to the control domain?

To: "Fajar A. Nugraha" <list@xxxxxxxxx>
Subject: Re: [Xen-users] XenServer adding additional CPUs to the control domain?
From: Pasi Kärkkäinen <pasik@xxxxxx>
Date: Wed, 5 Jan 2011 12:01:25 +0200
Cc: David Erickson <halcyon1981@xxxxxxxxx>, xen-users@xxxxxxxxxxxxxxxxxxx
Delivery-date: Wed, 05 Jan 2011 02:05:40 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <AANLkTikrfb27qjJfS80M9EJn5Q4gB8tc5zqscBVM_d2f@xxxxxxxxxxxxxx>
List-help: <mailto:xen-users-request@lists.xensource.com?subject=help>
List-id: Xen user discussion <xen-users.lists.xensource.com>
List-post: <mailto:xen-users@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=unsubscribe>
References: <AANLkTin1N3UEhorGWMjsXvF6Z7VQVgmWWCX+zKTSHxb6@xxxxxxxxxxxxxx> <AANLkTikrfb27qjJfS80M9EJn5Q4gB8tc5zqscBVM_d2f@xxxxxxxxxxxxxx>
Sender: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mutt/1.5.18 (2008-05-17)
On Mon, Jan 03, 2011 at 02:06:13PM +0700, Fajar A. Nugraha wrote:
> On Mon, Jan 3, 2011 at 12:57 PM, David Erickson <halcyon1981@xxxxxxxxx> wrote:
> > Hi all,
> > I have a large pool and when it syncs up the load on the control
> > domain of my pool is pretty high (I've seen up to 77..), I'd like to
> > add more than 1 cpu to it, is that possible?  I tried the suggestion
> > "echo 1 > /sys/devices/system/cpu/cpu1/online" followed by a reboot
> > but this didn't take, upon reboot all the cpus are back off.
> On "good" xen+dom0 kernel versions (like the one bundled in RHEL5), a
> simple "xm vcpu-set 0 4" (to assign 4 cpus to dom0) will do the trick
> just fine.
> On some "bad" xen+dom0 combinations, you might need to run "echo 1 >
> /sys/devices/system/cpu/cpu1/online" (no reboot needed) in addition to
> xm vcpu-set. On REALLY bad combination, even the above command won't
> work.
> So my suggestion is try "xm vcpu-set" route, and if doesn't work, you
> should seriously consider changing xen/dom0 kernel combination.

I think he's using Citrix XenServer, so "xm" tricks won't do it.

I'm not sure if XenServer has switched to multi-vcpu dom0 yet.. 
maybe in 5.6 FP1 ?

I know in earlier versions there were some bugs if you enabled
>1 vcpus manually..

Anyway, XenServer/XCP is planning to move to multi-vcpu dom0
at some point..

-- Pasi

Xen-users mailing list