WARNING - OLD ARCHIVES

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/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] cpuidle causing Dom0 soft lockups

To: Jan Beulich <JBeulich@xxxxxxxxxx>
Subject: Re: [Xen-devel] cpuidle causing Dom0 soft lockups
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Thu, 21 Jan 2010 11:03:55 +0000
Cc: "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Thu, 21 Jan 2010 03:04:21 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <4B58402E020000780002B3FE@xxxxxxxxxxxxxxxxxx>
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>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: Acqah/GTLClVfXuZSn+07GkspiPryQAAXqhO
Thread-topic: [Xen-devel] cpuidle causing Dom0 soft lockups
User-agent: Microsoft-Entourage/12.23.0.091001
On 21/01/2010 10:53, "Jan Beulich" <JBeulich@xxxxxxxxxx> wrote:

> But that's exactly why we use the polling method: That way we don't
> need to wake up all potential waiters, but just the one that's going to
> get the lock next. We now even go further and detect whether the
> lock owner is not currently running, and go polling right away (instead
> of spinning on the lock a few hundred times first).

Ah, these are pv spinlocks?

> I can see your point. But how can you consider shipping with something
> apparently severely broken. As said before - the fact that this manifests
> itself by hanging many-vCPU Dom0 has the very likely implication that
> there are (so far unnoticed) problems with smaller Dom0-s. If I had a
> machine at hand that supports C3, I'd try to do some measurements
> with smaller domains...

Well it's a fallback I guess. If we can't make progress on solving it then I
suppose I agree.

 -- Keir



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel