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] (XEN) HVM_PIT:missed ticks < 0

To: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] (XEN) HVM_PIT:missed ticks < 0
From: "Zhai, Edwin" <edwin.zhai@xxxxxxxxx>
Date: Mon, 24 Apr 2006 10:31:22 +0800
Cc: Ed Smith <esmith@xxxxxxxxxxxxxxx>, xen-devel Devel <xen-devel@xxxxxxxxxxxxxxxxxxx>, Edwin Zhai <edwin.zhai@xxxxxxxxx>
Delivery-date: Sun, 23 Apr 2006 19:32:23 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <d29bad6f759da48d9e4d47166481b7da@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>
References: <B99564216C25704085A82B41C46DD3420151B1B1@xxxxxxxxxxxxxxxxxxxxx> <d29bad6f759da48d9e4d47166481b7da@xxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mutt/1.5.11
On Sun, Apr 23, 2006 at 02:39:27PM +0100, Keir Fraser wrote:
> On 23 Apr 2006, at 14:03, Ed Smith wrote:
> >After yesterday's checkins to unstable, I can no longer boot an fully 
> >virtualized guest (Intel VT).? Here is an attempt at booting a 
> >RHEL4U2-32bit uniprocessor kernel guest.? The flood of '(XEN) 
> >HVM_PIT:missed ticks < 0' messages actually occur before getting to 
> >the guest's grub menu so the guest should not matter.
> I think this has started since Edwin Zhai's PIT emulation changes. I 
> applied a further patch from him to quieten down debug output for SMP 
> guests, but if those messages are coming out that early for you then it 
> looks like maybe the patch will only hide the underlying problem.
we have an optimization in original code: pit actimer will be stopped when the 
vcpu is sched out, so we have to check the missed ticks and rearm actimer when 
each vcpu is ched in with an inactive pit actimer. 

in smp environment, if cpu 0 has checked missed ticks in pit actimer function,
then cpu 1 will probably find no missed time(now < schedule time) and complain 
when sched in. 

in summary, this redundant debug info can be safely removed. but we'll come 
perfect pit solution for smp.

>  -- Keir


Xen-devel mailing list

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