kern/153620: Xen guest system clock drifts in AWS EC2 (FreeBSD 9.0-CURRENT i386 T1-micro)

[Greg Holmberg]

The following reply was made to PR kern/153620; it has been noted by GNATS.

From: Greg Holmberg <fbsd-9.0-aws-ec2-1293964000 at holmberg.to>
To: bug-followup at FreeBSD.org
Cc:  
Subject: Re: kern/153620: Xen guest system clock drifts in AWS EC2 (FreeBSD
 9.0-CURRENT i386 T1-micro)
Date: Sun, 2 Jan 2011 12:51:33 +0100

 On Sun, Jan 02, 2011 at 03:16:52AM -0800, Colin Percival wrote:
 >
 > Can you tell me:
 > 1. Did the clock run ahead, or behind?
 
 The NTP adjustment is a positive number (see below). Does this mean the
 clock is running slow?
 
 
 > 2. Can you reproduce this?
 >
                                                                                                                                
 Yes. In the existing AMI, I just reset the clock again. Since I filed
 the PR, it had drifted "offset 0.124360 sec". While writing this email,
 it has drifted another "offset 0.009534 sec". I will let it go without
 correction for a while now.
 
 
 > 3. Did the clock _drift_, or _jump_?
 >
                                                                                                                                
 Good question. Based on a handful of invocations of ntpdate, I would
 say that it drifts. The offset is different each time. ...
 
 Regards,
 
 Greg