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 system skew MUCH worse than tsc skew (was RE: [Xen-devel]RE: [PA

To: <dan.magenheimer@xxxxxxxxxx>, "Keir Fraser" <keir.fraser@xxxxxxxxxxxxx>, "Xen-Devel (E-mail)" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: RE: Xen system skew MUCH worse than tsc skew (was RE: [Xen-devel]RE: [PATCH] record max stime skew (was RE: [PATCH] strictly increasinghvm guest time))
From: "Tian, Kevin" <kevin.tian@xxxxxxxxx>
Date: Wed, 23 Jul 2008 14:11:51 +0800
Cc: Dave Winchell <dwinchell@xxxxxxxxxxxxxxx>
Delivery-date: Tue, 22 Jul 2008 23:14:07 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <20080722162717359.00000001992@djm-pc>
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>
References: <C4AA0829.245DF%keir.fraser@xxxxxxxxxxxxx> <20080722162717359.00000001992@djm-pc>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AcjcXTkqnSPaEESHRsmD1HhwJkyawAAAIPEpAAuAJ0AAAgl0IAAT2dqMABFKNxAAAHEqUAAGNaGwAAdfXjQAIb9HAAAAjWJ4AAico9AAAPZ0lAECdtJAABGXRyYAHMJkcAAXKn0wAaR9gGAAUpgMiQBOeNLwABESLpA=
Thread-topic: Xen system skew MUCH worse than tsc skew (was RE: [Xen-devel]RE: [PATCH] record max stime skew (was RE: [PATCH] strictly increasinghvm guest time))
>From: Dan Magenheimer
>Sent: 2008年7月23日 6:27
>
>Perhaps some form of the proposed "deferrable timers" can
>be used to ensure per-cpu calibration happens on different
>processors at roughly the same moment?
>

It can't. Deferrable timer is a per-cpu concept, to rendezvous
what can be deferred on local cpu. There's nothing to 
coordinate across-cpu activities, for which Instead you have to 
use some form of IPIs and self-defined sync process as what
Ian suggested.

Thanks,
Kevin

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

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