I'm running chrony 4.5 (which is the current default) on a commercial Microsoft Azure VM (Linux myVm 6.8.0-1021-azure). By default a PTP hardware clock is used as a time source:
chrony.conf has no servers defined
refclock PHC /dev/ptp_hyperv poll 3 dpoll -2 offset 0
No external servers are defined. This is the default configuration.
Current time source: hyperv_clocksource_tsc_page
Available time sources: hyperv_clocksource_tsc_page hyperv_clocksource_msr acpi_pm
This is the default setting.
AFAICT chrony is happy, but is providing inaccurate time: Time is in error by 30-50 msec with substantial jitter.
Dropping the PHC refclock and using nearby stratum 1's give much better results.
Any suggestions for further debugging?