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


[Xen-devel] Re: [PATCH 1/5] Add a global synchronization point for pvclo

To: Avi Kivity <avi@xxxxxxxxxx>
Subject: [Xen-devel] Re: [PATCH 1/5] Add a global synchronization point for pvclock
From: Glauber Costa <glommer@xxxxxxxxxx>
Date: Tue, 26 Oct 2010 08:49:22 -0200
Cc: Jeremy Fitzhardinge <jeremy@xxxxxxxx>, Marcelo Tosatti <mtosatti@xxxxxxxxxx>, kvm@xxxxxxxxxxxxxxx, Zachary Amsden <zamsden@xxxxxxxxxx>, linux-kernel@xxxxxxxxxxxxxxx, "Xen-devel@xxxxxxxxxxxxxxxxxxx" <Xen-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Tue, 26 Oct 2010 03:50:15 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <4CC68DE1.1060604@xxxxxxxxxx>
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/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Organization: Red Hat Inc.
References: <1271356648-5108-1-git-send-email-glommer@xxxxxxxxxx> <1271356648-5108-2-git-send-email-glommer@xxxxxxxxxx> <4CC6130B.8020908@xxxxxxxx> <4CC68DE1.1060604@xxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
On Tue, 2010-10-26 at 10:14 +0200, Avi Kivity wrote:
> On 10/26/2010 01:30 AM, Jeremy Fitzhardinge wrote:
> > Unfortunately this is breaking Xen save/restore: if you restore on a
> > host which was booted more recently than the save host, causing the
> > system time to be smaller.  The effect is that the domain's time leaps
> > forward to a fixed point, and stays there until the host catches up to
> > the source host...
> Shouldn't save/restore also save the timebase?
> > I guess last_time needs to be reset on this type of event.  I guess the
> > cleanest way would be for pvclock.c to register a sysdev suspend/resume
> > handler.
> Should be for Xen only; kvm save/restore doesn't involve the guest.

the suspend/resume path do adjust the time base. Maybe something similar
should be done ?

Xen-devel mailing list

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