Date: Fri, 10 Apr 2015 10:35:48 -0700 From: Paul Vixie <paul@redbarn.org> To: freebsd-virtualization@freebsd.org Subject: bhyve clock problem, solved by kern.timecounter.hardware="TSC-low" in /etc/sysctl.conf Message-ID: <552809F4.6070206@redbarn.org>
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here is a representative one-hour sample of ntp messages from /var/log/messages on a freebsd 10.1 bhyve guest: > Apr 10 12:00:46 family ntpd[634]: time reset -0.613057 s > Apr 10 12:17:02 family ntpd[634]: time reset -0.604933 s > Apr 10 12:33:51 family ntpd[634]: time reset -0.650622 s > Apr 10 12:55:06 family ntpd[634]: time reset -0.743930 s that's with kern.timecounter.hardware: HPET, which is the default. a "time reset" from ntpd means the clock either won't slew at all or can't slew fast enough. in other words a normal freebsd 10.1 server can run for months or even years without ever outputting one of these messages. google reports that some folks have had good luck with kern.timecounter.hardware: TSC-low. so i tried that on another freebsd 10.1 bhyve guest on the same bhyve server, with dramatic results -- no more ntpd messages. can we make TSC-low the default? vixie
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