Major Description
We have seen issues with both Xen 7.2 and 7.4 in regards to NTP drifts while clocksource set to tsc. We ran some other tests using a bare-metal install of CentOS7 as well as VMWare ESXi 6.5 and do not see the same issue running on the same hardware - We have been trying to get answers from SuperMirco on perhaps a BIOS update that may fix this issue. When we forced clocksource to xen instead of tsc we don't see the ntp drift issue anymore. Our only workaround at this point is to setup a cronjob to restart NTP every min or so at this point in time.
