Date: Fri, 20 Oct 2017 10:32:40 -0600 From: Ian Lepore <ian@freebsd.org> To: Boris Samorodov <bsam@passap.ru>, freebsd-current@FreeBSD.org Subject: Re: host, bhyve vm and ntpd Message-ID: <1508517160.1383.63.camel@freebsd.org> In-Reply-To: <bf8eae88-ee44-58d5-bb3a-565a0314fdfe@passap.ru> References: <2931f1cc-6574-b58d-4b94-5f77fa5cdb85@passap.ru> <1508512327.1383.55.camel@freebsd.org> <39bf2426-2edf-d485-7c81-519e931154be@passap.ru> <bf8eae88-ee44-58d5-bb3a-565a0314fdfe@passap.ru>
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On Fri, 2017-10-20 at 18:36 +0300, Boris Samorodov wrote: > 20.10.2017 18:31, Boris Samorodov ΠΙΫΕΤ: > > > > 20.10.2017 18:12, Ian Lepore ΠΙΫΕΤ: > > > > > > On Fri, 2017-10-20 at 14:46 +0300, Boris Samorodov wrote: > > > > > > > > Hi All, > > > > > > > > I have got a host: > > > > --- > > > > bhyve-host% uname -a > > > > FreeBSD sm.bsnet 12.0-CURRENT FreeBSD 12.0-CURRENT #3 r322868: Fri Aug > > > > 25 05:25:26 MSK 2017 > > > > bsam@builder.bsnet:/usr/obj/usr/src/sys/GENERIC-FASTamd64 amd64 > > > > --- > > > > > > > > And a bhyve vm: > > > > --- > > > > bhyve-vm: uname -a > > > > FreeBSD builder.bsnet 12.0-CURRENT FreeBSD 12.0-CURRENT #58 r324782: Fri > > > > Oct 20 05:12:17 MSK 2017 > > > > bsam@builder.bsnet:/usr/obj/usr/src/sys/PKG64Xamd64 amd64 > > > > --- > > > > > > > > The only difference at kernel configs is a colored console. :-) > > > > > > > > And here I get some weird (is it?) result at the VM (I expect ntpd to be > > > > more stable): > > > > --- > > > > bhyve-vm% for t in `jot 10`; do ntpq -pn; sleep 64; done > > > > remoterefidst t when poll reachdelayoffset > > > > jitter > > > > ============================================================================== > > > > XX.XX.XX.1XX.XX.XX.2454 u96430.605-1.202 > > > > 316.407 > > > > XX.XX.XX.1XX.XX.XX.2454 u76470.605-1.202 > > > > 358.395 > > > > *XX.XX.XX.1XX.XX.XX.2454 u564170.615-328.42 > > > > 181.405 > > > > *XX.XX.XX.1XX.XX.XX.2454 u364370.615-328.42 > > > > 214.868 > > > > *XX.XX.XX.1XX.XX.XX.2454 u6764370.615-328.42 > > > > 214.868 > > > > *XX.XX.XX.1XX.XX.XX.2454 u6364770.615-328.42 > > > > 268.618 > > > > *XX.XX.XX.1XX.XX.XX.2454 u60641770.615-328.42 > > > > 333.175 > > > > XX.XX.XX.1.STEP.16 u 19106400.0000.000 > > > > 0.000 > > > > XX.XX.XX.1XX.XX.XX.2454 u276410.703-262.63 > > > > 0.004 > > > > XX.XX.XX.1XX.XX.XX.2454 u316410.649-331.43 > > > > 68.800 > > > > --- > > > > > > > > At the same time host's results are very stable: > > > > --- > > > > bhyve-host% for t in `jot 10`; do ntpq -pn; sleep 64; done > > > > remoterefidst t when poll reachdelayoffset > > > > jitter > > > > ============================================================================== > > > > > > > > > > > > > > > > *XX.XX.XX.1XX.XX.XX.2454 u16410.4010.176 > > > > 0.106 > > > > *XX.XX.XX.1XX.XX.XX.2454 u66430.4010.176 > > > > 0.459 > > > > *XX.XX.XX.1XX.XX.XX.2454 u36470.4010.176 > > > > 0.940 > > > > *XX.XX.XX.1XX.XX.XX.2454 u676470.4010.176 > > > > 0.940 > > > > *XX.XX.XX.1XX.XX.XX.2454 u6464170.4010.176 > > > > 1.566 > > > > *XX.XX.XX.1XX.XX.XX.2454 u6064370.4481.275 > > > > 1.739 > > > > *XX.XX.XX.1XX.XX.XX.2454 u5564770.4481.275 > > > > 2.365 > > > > *XX.XX.XX.1XX.XX.XX.2454 u53641770.4481.275 > > > > 3.110 > > > > *XX.XX.XX.1XX.XX.XX.2454 u50643770.4481.275 > > > > 3.929 > > > > *XX.XX.XX.1XX.XX.XX.2454 u45643770.4438.750 > > > > 4.722 > > > > --- > > > > > > > > The network is organized via bridge -- host igb and vm tap interfaces > > > > are members of one bridge. > > > > > > > > Are those results expected? Does it smell like a bug? Should I dig > > > > furter? > > > > > > > So it is repeatedly stepping the clock in the VM? (Set > > > kern.timecounter.stepwarnings=1 to log steps). > > No kernel/ntpd messages for 20 minutes after setting this sysctl. > > > > > > > > That is usually a sign > > > that the chosen timecounter is running at a different frequency than it > > > claimed to be when it registered itself -- the host may not be > > > emulating the timer hardware properly in the guest. What is the output > > > of sysctl kern.timecounter in the vm? > > --- > > bhyve-vm% sysctl kern.timecounter > > > > kern.timecounter.tsc_shift: 1 > > kern.timecounter.smp_tsc_adjust: 0 > > kern.timecounter.smp_tsc: 0 > > kern.timecounter.invariant_tsc: 1 > > kern.timecounter.fast_gettime: 1 > > kern.timecounter.tick: 1 > > kern.timecounter.choice: ACPI-fast(900) HPET(950) i8254(0) TSC-low(-100) > > dummy(-1000000) > > kern.timecounter.hardware: HPET > > kern.timecounter.alloweddeviation: 5 > > kern.timecounter.stepwarnings: 1 > > kern.timecounter.tc.ACPI-fast.quality: 900 > > kern.timecounter.tc.ACPI-fast.frequency: 3579545 > > kern.timecounter.tc.ACPI-fast.counter: 4161213491 > > kern.timecounter.tc.ACPI-fast.mask: 4294967295 > > kern.timecounter.tc.HPET.quality: 950 > > kern.timecounter.tc.HPET.frequency: 10000000 > > kern.timecounter.tc.HPET.counter: 3518036865 > > kern.timecounter.tc.HPET.mask: 4294967295 > > kern.timecounter.tc.i8254.quality: 0 > > kern.timecounter.tc.i8254.frequency: 1193182 > > kern.timecounter.tc.i8254.counter: 47597 > > kern.timecounter.tc.i8254.mask: 65535 > > kern.timecounter.tc.TSC-low.quality: -100 > > kern.timecounter.tc.TSC-low.frequency: 1199886114 > > kern.timecounter.tc.TSC-low.counter: 1274338278 > > kern.timecounter.tc.TSC-low.mask: 4294967295 > > --- > BTW, here is the host kern.timecounter: > --- > kern.timecounter.tsc_shift: 1 > kern.timecounter.smp_tsc_adjust: 0 > kern.timecounter.smp_tsc: 1 > kern.timecounter.invariant_tsc: 1 > kern.timecounter.fast_gettime: 1 > kern.timecounter.tick: 1 > kern.timecounter.choice: ACPI-fast(900) HPET(950) i8254(0) TSC-low(1000) > dummy(-1000000) > kern.timecounter.hardware: TSC-low > kern.timecounter.alloweddeviation: 5 > kern.timecounter.stepwarnings: 0 > kern.timecounter.tc.ACPI-fast.quality: 900 > kern.timecounter.tc.ACPI-fast.frequency: 3579545 > kern.timecounter.tc.ACPI-fast.counter: 9047194 > kern.timecounter.tc.ACPI-fast.mask: 16777215 > kern.timecounter.tc.HPET.quality: 950 > kern.timecounter.tc.HPET.frequency: 14318180 > kern.timecounter.tc.HPET.counter: 2232552795 > kern.timecounter.tc.HPET.mask: 4294967295 > kern.timecounter.tc.i8254.quality: 0 > kern.timecounter.tc.i8254.frequency: 1193182 > kern.timecounter.tc.i8254.counter: 43410 > kern.timecounter.tc.i8254.mask: 65535 > kern.timecounter.tc.TSC-low.quality: 1000 > kern.timecounter.tc.TSC-low.frequency: 1200067168 > kern.timecounter.tc.TSC-low.counter: 2463146362 > kern.timecounter.tc.TSC-low.mask: 4294967295 > --- > > > > > > > > > Also, what is the output of ntptime(8) in the vm? > > --- > > bhyve-vm% ntptime > > > > ntp_gettime() returns code 0 (OK) > > time dd94930f.20ea2900Fri, Oct 20 2017 18:21:51.128, (.128573699), > > maximum error 1309110 us, estimated error 3 us, TAI offset 37 > > ntp_adjtime() returns code 0 (OK) > > modes 0x0 (), > > offset 0.000 us, frequency 0.000 ppm, interval 1 s, > > maximum error 1309110 us, estimated error 3 us, > > status 0x2001 (PLL,NANO), > > time constant 6, precision 0.001 us, tolerance 496 ppm, > > --- > > > > Ian, thank you for your help! > > > It seems odd to me that the frequency of the host HPET is 14.3mhz and that of the guest is 10.0mhz, but maybe that's a normal condition for bhyve. I did find some google hits[1] for bhyve guest timekeeping trouble with the HPET timer which was solved by switching to a different timecounter. Timecounter choices can't be controlled from loader.conf, so I guess a sysctl.conf entry of kern.timecounter.hardware="ACPI-fast" is the only way to fix that. You can also just do that command interactively first and see if it stops the time steps and ntp settles down. This would be a workaround, not a fix per se. If the time steps go away, then something in bhyve's emulation of HPET (maybe only on some hardware?) must be buggy. [1] https://lists.freebsd.org/pipermail/freebsd-virtualization/2015-April/003492.html -- Ian
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