Date: Fri, 10 Apr 2015 17:47:23 -0500 From: Matthew Grooms <mgrooms@shrew.net> To: freebsd-virtualization@freebsd.org Subject: Re: bhyve clock problem, solved by kern.timecounter.hardware="TSC-low" in /etc/sysctl.conf Message-ID: <552852FB.1060901@shrew.net> In-Reply-To: <CAOb7DXGAWiTUvmq5xJT8Z8W9D3hFuWeHQ-vbADw2AP0Fv4e8Lw@mail.gmail.com> References: <552809F4.6070206@redbarn.org> <CAOb7DXGAWiTUvmq5xJT8Z8W9D3hFuWeHQ-vbADw2AP0Fv4e8Lw@mail.gmail.com>
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Perhaps applying this commit would have some positive effect ( HPET vs LAPIC )? https://docs.freebsd.org/cgi/getmsg.cgi?fetch=885358+0+archive/2015/svn-src-head/20150322.svn-src-head -Matthew On 4/10/2015 12:51 PM, Stephen Stuart wrote: > I think the right thing is to set (in /boot/loader.conf) > kern.timecounter.tc.TSC-low.quality to a value higher than that for HPET, > to force the clock choice over what the kernel decides for the hardware > that you're running on. See timecounters(4). > > Stephen > > On Fri, Apr 10, 2015 at 10:35 AM, Paul Vixie <paul@redbarn.org> wrote: > >> 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 >> >> >> _______________________________________________ >> freebsd-virtualization@freebsd.org mailing list >> http://lists.freebsd.org/mailman/listinfo/freebsd-virtualization >> To unsubscribe, send any mail to " >> freebsd-virtualization-unsubscribe@freebsd.org" >> > _______________________________________________ > freebsd-virtualization@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-virtualization > To unsubscribe, send any mail to "freebsd-virtualization-unsubscribe@freebsd.org"
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