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] RE: [PATCH] rendezvous-based local time calibration WOW!

To: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>
Subject: Re: [Xen-devel] RE: [PATCH] rendezvous-based local time calibration WOW!
From: John Levon <levon@xxxxxxxxxxxxxxxxx>
Date: Tue, 5 Aug 2008 22:12:51 +0100
Cc: Ian Pratt <Ian.Pratt@xxxxxxxxxxxxx>, "Xen-Devel \(E-mail\)" <xen-devel@xxxxxxxxxxxxxxxxxxx>, Dave Winchell <dwinchell@xxxxxxxxxxxxxxx>, Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Delivery-date: Tue, 05 Aug 2008 14:13:35 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <20080805144925125.00000008444@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: <20080805185651.GB9615@xxxxxxxxxxxxxxxxxxxxxxx> <20080805144925125.00000008444@djm-pc>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mutt/1.5.9i
On Tue, Aug 05, 2008 at 02:49:25PM -0600, Dan Magenheimer wrote:

> The algorithm used to compute the timestamp information

Thanks.

> I'm not sure its possible to guarantee monotonicity in
> PV domains (without a global lock) except by doing a trap
> or hypercall at each "get time".

That's a shame.

> I've thought about implementing softtsc for PV domains for
> this reason.  (Softtsc was just added at 4.0 for hvm domains
> and causes all hvm tsc reads to trap.)  Would this be of
> interest?

No, as it would be incredibly slow on Solaris (I dread to imagine).

regards,
john

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

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