TSC calibration in virtual machines

[Andriy Gapon]

It seems that TSC calibration in virtual machines sometimes can do more harm
than good.  Should we default to trusting the information provided by a hypervisor?

Specifically, I am observing a problem on GCE instances where calibrated TSC
frequency is about 10% lower than advertised frequency.  And apparently the
advertised frequency is the right one.

I found this thread with similar reports and a variety of workarounds from
administratively disabling the calibration to switching to a different timecounter:
https://lists.freebsd.org/pipermail/freebsd-cloud/2017-January/000080.html

-- 
Andriy Gapon