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] [PATCH 1/2] cpu steal time accounting

To: Dan Hecht <dhecht@xxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH 1/2] cpu steal time accounting
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Thu, 23 Feb 2006 08:40:43 +0000
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
Delivery-date: Thu, 23 Feb 2006 08:42:37 +0000
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <43FCFA9F.8080407@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/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: <43FCCB2C.5000408@xxxxxxxxxx> <43FCFA9F.8080407@xxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx

On 22 Feb 2006, at 23:58, Dan Hecht wrote:

To solve this, it may be best to have the hypervisor interface expose per-vcpu stolen time directly, rather than vcpu_time. Then the guest does not need to try to guess whether to charge (system_time - vcpu_time) against idle or steal.

Yes, the distinction between stolen and available time does makes sense (although I'm not sure 'available' is a great name) otherwise you can't account for wakeup latencies. account_steal_time() would need to be modified in Linux, though, as we would not need its dodgy heuristic for deciding whether to account to stolen time or iowait/idle.

 -- Keir

Xen-devel mailing list