Hi Ian, I think this is a common problem, and has been an issue from time to time on KVM machines also, you can try an alternate counter and see how you get on, if you check out Mischa Peters talk on VMM he has some workarounds that he has deployed in production. but for an NTP server the accuracy of the clock may cause you too much problems..
as I said we had issues before with KVM and the timecounter hardware... but the newer timecounters in recent versions of OpenBSD have worked really well for us. I hope this helps, Tom Smyth On Tue, 3 Mar 2020 at 17:05, Ian Gregory <[email protected]> wrote: > > On Tue, 3 Mar 2020 at 15:47, mabi <[email protected]> wrote: > > It looks like there is a time issue on that VM although I am running the > > default ntpd of OpenBSD 6.6 and I have added the following parameter into > > my /etc/sysctl.conf on that VM: > > > > kern.timecounter.hardware=tsc > > I've had similar issues with timekeeping within guests of VMM, > although there are improvements in -current with the pvclock time > source. Since the fix below I now see occasional instances of the > clock stepping by a few whole seconds (typically less than 8s) but > it's much less frequent and the magnitude is within the bounds of what > ntpd can correct. > > See > http://openbsd-archive.7691.n7.nabble.com/pvclock-stability-tp376946p377922.html > for some backstory > > (aside: I see similar small occasional clock jumps of an integer > number of seconds on OpenBSD-6.6 guests using tsc running on a VMware > ESXi host) > > Regards > Ian > -- Kindest regards, Tom Smyth.
