Xen 3.2.2 - Timer ISR/0: Time went backwards

["Christopher S. Aker" <caker@theshore.net>]

Hardware:
Xen: 3.2.1-rc2 64bit
dom0: 2.6.18.8 at changeset 622, PAE

# xm dmesg | grep -e sync -e timer
(XEN) checking TSC synchronization across 8 CPUs: passed.
(XEN) Platform timer overflows in 234 jiffies.
(XEN) Platform timer is 3.579MHz ACPI PM Timer
(XEN) Machine check exception polling timer started.

Spools one of these to console every few seconds:

Timer ISR/0: Time went backwards: delta=-4270576170971 
delta_cpu=254829029 shadow=2037844042151244163 off=261710497 
processed=2037848312989081849 cpu_processed=2037844042158081849
  0: 2037844042158081849
  1: 2037828468354081849
  2: 2037848312989081849
  3: 2037837726866081849
  4: 2037842059197081849
  5: 2037840075526081849
  6: 2037845844663081849
  7: 2037841593777081849

A few t's into Xen's console:

(XEN) *** Serial input -> Xen (type 'CTRL-a' three times to switch input 
to DOM0)
(XEN) Min = 2037829427350793281 ; Max = 2037848310626701146 ; Diff = 
18883275907865 (18883275907 microseconds)
(XEN) Min = 2037829428349256182 ; Max = 2037848311625163843 ; Diff = 
18883275907661 (18883275907 microseconds)
(XEN) Min = 2037829428565188930 ; Max = 2037848311841096807 ; Diff = 
18883275907877 (18883275907 microseconds)

This particular box does this with 3.2.0 - 3.2.2-rc2.  I have another 
box doing the same thing, except the delta is more sane (0 - 2 
microseconds), however eventually dom0 freezes.

-Chris