22.10.2017 18:22, Rodney W. Grimes пишет:
> [ Charset UTF-8 unsupported, converting... ]
>> 22.10.2017 01:15, Ian Lepore ?????:
>>> On Sat, 2017-10-21 at 17:07 -0400, Michael Voorhis wrote:
>>>> Ian Lepore writes:
>>>>> Beyond that, I'm not sure what else to try. ?It might be necessary to
>>>>> get some bhyve developers involved (I know almost nothing about it).
>>>> NTPD behaves more normally on uniprocessor VMs.
>>>> A FreeBSD bhyve-guest running on a freebsd host will select a
>>>> different timecounter depending on whether it is a multiprocessor or a
>>>> uniprocessor.??My uniprocessor bhyve-vm selected TSC-low as the best
>>>> timecounter in a uniprocessor.??NTP functions there as expected.
>>>> kern.timecounter.choice: TSC-low(1000) ACPI-fast(900) HPET(950) i8254(0)
>>>> kern.timecounter.hardware: TSC-low
>>>> The very same VM, when given two total CPUs, selected HPET (if I
>>>> recall) and the timekeeping with NTPD was unreliable, with many
>>>> step-resets to the clock.
>>> Hmm, I just had glance at the code in?sys/amd64/vmm/io/vhpet.c and it
>>> looks right. ?I wonder if this is just a simple roundoff error in
>>> converting between 10.0MHz and SBT units? ?If so, that could be wished
>>> away easily by using a power-of-2 frequency for the virtual HPET. ?I
>>> wonder if the attached patch is all that's needed?
>> I've tried the patch (at bhyve guest) and nothing has changed. Should
>> the patched system be tested at bhyve guest or bhyve host?
> I believe the suggested patch would have to be made to the bhyve
OK, I'd do it tomorrow and report back.
>. Also on the host and guest what are the values of
> sysctl kern.timecounter.tc.HPET
> sysctl kern.timecounter.tc.i8254
Here they are:
bhyve-host% sysctl kern.timecounter.tc.HPET
bhyve-host% sysctl kern.timecounter.tc.i8254
bhyve-guest% sysctl kern.timecounter.tc.HPET
bhyve-guest% sysctl kern.timecounter.tc.i8254
> Getting good ntpd behavior in a VM guest of any kind is sometimes a
> non trivial thing to do.
As a side note, I have a CentOS-7 bhyve VM at the same host.
And it was enough to run chronyd with default config. Which stepped
twice and is stable (no messages) for several days, current log:
Oct 19 16:01:03 c.vpn systemd: Starting NTP client/server...
Oct 19 16:01:03 c.vpn chronyd: chronyd version 3.1 starting
(+CMDMON +NTP +REFCLOCK +RTC +PRIVDROP +SCFILTER +SECHASH +SIGND
+ASYNCDNS +IPV6 +DEBUG)
Oct 19 16:01:03 c.vpn chronyd: Frequency 0.000 +/- 1000000.000
ppm read from /var/lib/chrony/drift
Oct 19 16:01:03 c.vpn systemd: Started NTP client/server.
Oct 19 16:01:07 c.vpn chronyd: Selected source XX.XX.XX.1
Oct 19 16:01:07 c.vpn chronyd: System clock wrong by -44.392782
seconds, adjustment started
Oct 19 16:00:23 c.vpn chronyd: System clock was stepped by
Oct 19 16:00:34 c.vpn chronyd: System clock was stepped by
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