kern.timecounter.choice - possible values on a domU?

["Dirk H. Schulz" <dirk.schulz%kinzesberg.de@localhost>]

Hi folks,

I am looking deeply into xen and NetBSD with my Xen/Linux knowledge. 
That makes things difficult, so please bear with me. :-)

I am looking for a way to make the system clock of a NetBSD domU 
independent  from the host systems hardware clock (I want to run ntpdate 
inside the domU) like it's done on Linux domUs with the 
independent_wallclock kernel parameter.

Poking around in the sysctl value list I found
   kern.timecounter.choice
which sounds like the parameter to tune. But I did not find any 
documentation on the possible values of this parameter. So the questions 
are:

- if there is documentation on this, where do I find it? (As I said, I 
am new to NetBSD, and there is a lot to learn yet)
- if there is no documentation on this: What are the possible values, 
and what do I use to make domU's clock independent?

Thanks in advance,

Dirk