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-devel] Dom0 <> DomU clock sync

To: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] Dom0 <> DomU clock sync
From: Sébastien RICCIO <sr@xxxxxxxxxxxxxxx>
Date: Mon, 03 Sep 2007 16:37:52 +0200
Cc: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Mon, 03 Sep 2007 07:39:19 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <C301D60A.1520D%Keir.Fraser@xxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Organization: OpenBusiness SA / SwissCenter
References: <C301D60A.1520D%Keir.Fraser@xxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Thunderbird (Windows/20070728)
Hi again,

I just tried to use ntpd in dom0. So far nothing changed.
The guests are still a couple of minutes behind the dom0.

Dom0 and DomU's are set to independent_wallclock 0.

Kernels are compiled from the sources included in Xen 3.1.

I don't know where to head next :))

Thanks for your help.

Sébastien Riccio
SwissCenter / OpenBusiness SA

Keir Fraser a écrit :
On 3/9/07 15:07, "Sébastien RICCIO" <sr@xxxxxxxxxxxxxxx> wrote:

Ntpd is not running in dom0. I am updating the dom0 time with ntpdate
(crontab every hour).
Should ntpd be running on dom0 ?

So long as ntpdate calls settimeofday(), this should be sufficient to update
Xen's notion of time too. It seems that isn't happening for some reason.

Do all guests (including dom0) have independent_wallclock equal to 0?

What kernel are you using in dom0 (e.g., vendor kernel?).

Ntpd in dom0 would be an interesting thing to try. That should cause dom0 to
periodically (every few minutes) push its time down to Xen to be picked up
by all domUs. But really ntpdate should be doing the right thing...

In our kernels it should be *impossible* for dom0 and domU time to diverge
when independent_wallclock is set to zero everywhere...

 -- Keir

Xen-devel mailing list

Xen-devel mailing list

<Prev in Thread] Current Thread [Next in Thread>