Bhyve guest ntp server woes

[Adam Vande More]

I am unable to get a 10.2 bhyve ntp server to be stable.

Most configurations of

kern.timecounter.*
sysctl kern.eventtimer.*

in the guest seem to make little difference, however
kern.eventtimer.periodic=1 does seem to stabilize it a little.  However
after some runtime, I get very high jitter and offsets and extraordinary
dispersion and distance values when seen from the host using guest as
server(not actually sync'd against).

How can I get some sane ntp in bhyve?

Thanks,

-- 
Adam