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] blocking Xen 3.X production use: soft lockup bugs

To: Steve Traugott <stevegt@xxxxxxxxxxxxx>
Subject: Re: [Xen-devel] blocking Xen 3.X production use: soft lockup bugs
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Sat, 05 Aug 2006 09:50:29 +0100
Cc: Ian Pratt <m+Ian.Pratt@xxxxxxxxxxxx>, xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Sat, 05 Aug 2006 01:59:01 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <20060804202121.GA13827@xxxxxxxxxxxxx>
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>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: Aca4bDOzcjOThyRfEduqRAANk04WTA==
Thread-topic: [Xen-devel] blocking Xen 3.X production use: soft lockup bugs
User-agent: Microsoft-Entourage/
On 4/8/06 9:21 pm, "Steve Traugott" <stevegt@xxxxxxxxxxxxx> wrote:

> You nailed it, Keir.
> On Thu, Aug 03, 2006 at 09:03:18AM +0100, Keir Fraser wrote:
>> Also older versions using sedf scheduler (which has now been patched to
>> avoid this) could end up with domain0 consuming all CPU and starving
>> other guests, leading to softlockup errors. We haven't seen any such
>> errors on our own test machines since this was fixed. Of course, that
>> doesn't mean there aren't problems with other test scenarios!
> That is exactly what was happening.  I did more testing yesterday and
> last night (-testing changeset 9732), and realized that I was only
> seeing soft lockups on the second of two domU guests, and only when
> running a heavy load in dom0.  According to 'xm vcpu-list' the second
> guest was on CPU 0, as was the workload in dom0...  I added more
> workload processes to consume both CPUs in dom0, and of course when I
> did that, the first guest ground to a halt and started showing soft
> lockups as well.

It's *always* worth trying the tip of 3.0-testing if you're seeing problems
with a strictly older version. In this case there are about 50 newer
changesets, many of which are the result of aggressive testing by Suse for
SLES10. Well worth having.

 -- Keir

Xen-devel mailing list