Date: Wed, 10 Oct 2012 23:30:30 -0700 From: John-Mark Gurney <jmg@funkthat.com> To: Alexander Motin <mav@FreeBSD.org> Cc: freebsd-stable@FreeBSD.org Subject: Re: time keeps on slipping... slipping... Message-ID: <20121011063030.GK1967@funkthat.com> In-Reply-To: <5075F9F7.1040007@FreeBSD.org> References: <20121008040239.GE1967@funkthat.com> <5075F9F7.1040007@FreeBSD.org>
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Alexander Motin wrote this message on Thu, Oct 11, 2012 at 01:43 +0300:
> On 08.10.2012 07:02, John-Mark Gurney wrote:
> >I recently put together a new machine w/ a SuperMicro H8SCM and an
> >AMD Opteron 4228 HE... I've having an issue where the clock on the
> >machine skips around... The wierd part is that it's very sudden when
> >it happens... ntp sometimes brings it back, but it can't when the clock
> >gets too far ahread (1000 seconds), ntp dies...
> >
> >In order to catch it happening, I ran a sleep 60 loop fetching time
> >from another server that keeps time correctly via:
> >while sleep 60; do echo -n h2:; nc h2 13; date; ntpdate h2.funkthat.com;
> >done
> >
> >here are some snippits:
> >h2:Sun Oct 7 17:12:54 2012^M
> >Sun Oct 7 17:12:54 PDT 2012
> > 7 Oct 17:12:54 ntpdate[31036]: the NTP socket is in use, exiting
> >h2:Sun Oct 7 17:13:48 2012^M
> >Sun Oct 7 17:20:21 PDT 2012
> > 7 Oct 17:20:21 ntpdate[31045]: the NTP socket is in use, exiting
> >
> >but then ntp brings it back in sync:
> >h2:Sun Oct 7 17:28:49 2012^M
> >Sun Oct 7 17:35:21 PDT 2012
> > 7 Oct 17:35:21 ntpdate[31164]: the NTP socket is in use, exiting
> >h2:Sun Oct 7 17:29:49 2012^M
> >Sun Oct 7 17:29:49 PDT 2012
> > 7 Oct 17:29:49 ntpdate[31170]: the NTP socket is in use, exiting
> >
> >It happens pretty often:
> >Oct 7 00:19:13 gold ntpd[3721]: time reset -785.347912 s
> >Oct 7 00:46:37 gold ntpd[3721]: time reset -392.673256 s
> >Oct 7 01:04:24 gold ntpd[3721]: time reset -785.346533 s
> >Oct 7 15:00:59 gold ntpd[3721]: time reset -392.681720 s
> >Oct 7 16:32:11 gold ntpd[3721]: time reset -392.671268 s
> >Oct 7 17:29:29 gold ntpd[3721]: time reset -392.671752 s
> >Oct 7 18:04:37 gold ntpd[3721]: time reset -785.346987 s
> >
> >but as you can see above, the time slip happens abruptly.. looks like
> >a rounding error or something...
> >
> >I'm now reducing the sleep to 5 seconds... but as you can see the sleep
> >ends a few seconds early and local time suddenly jumped forward 6
> >minutes 33 seconds...
> >
> >$ sysctl kern.timecounter
> >kern.timecounter.fast_gettime: 1
> >kern.timecounter.tick: 1
> >kern.timecounter.choice: TSC-low(1000) ACPI-safe(850) HPET(950) i8254(0)
> >dummy(-1000000)
> >kern.timecounter.hardware: TSC-low
> >kern.timecounter.stepwarnings: 0
> >kern.timecounter.tc.i8254.mask: 65535
> >kern.timecounter.tc.i8254.counter: 11598
> >kern.timecounter.tc.i8254.frequency: 1193182
> >kern.timecounter.tc.i8254.quality: 0
> >kern.timecounter.tc.HPET.mask: 4294967295
> >kern.timecounter.tc.HPET.counter: 3257069245
> >kern.timecounter.tc.HPET.frequency: 14318180
> >kern.timecounter.tc.HPET.quality: 950
> >kern.timecounter.tc.ACPI-safe.mask: 16777215
> >kern.timecounter.tc.ACPI-safe.counter: 4219134510
> >kern.timecounter.tc.ACPI-safe.frequency: 3579545
> >kern.timecounter.tc.ACPI-safe.quality: 850
> >kern.timecounter.tc.TSC-low.mask: 4294967295
> >kern.timecounter.tc.TSC-low.counter: 2854866610
> >kern.timecounter.tc.TSC-low.frequency: 10937740
> >kern.timecounter.tc.TSC-low.quality: 1000
> >kern.timecounter.smp_tsc: 1
> >kern.timecounter.invariant_tsc: 1
> >$ sysctl kern.eventtimer
> >kern.eventtimer.choice: LAPIC(400) i8254(100) RTC(0)
> >kern.eventtimer.et.LAPIC.flags: 15
> >kern.eventtimer.et.LAPIC.frequency: 100002217
> >kern.eventtimer.et.LAPIC.quality: 400
> >kern.eventtimer.et.i8254.flags: 1
> >kern.eventtimer.et.i8254.frequency: 1193182
> >kern.eventtimer.et.i8254.quality: 100
> >kern.eventtimer.et.RTC.flags: 17
> >kern.eventtimer.et.RTC.frequency: 32768
> >kern.eventtimer.et.RTC.quality: 0
> >kern.eventtimer.periodic: 0
> >kern.eventtimer.timer: LAPIC
> >kern.eventtimer.activetick: 1
> >kern.eventtimer.idletick: 0
> >kern.eventtimer.singlemul: 2
> >
> >I have switched my timecounter to HPET to see if things are different...
> >
> >Any clues?
>
> Mentioned switching to HPET could tell a lot about the problem.
> Switching event timer also may be interesting.
Since I switch to HPET, it hasn't happened at all in the last 3 days..
Should I try switching back to TSC and switching event timer? do you
need any other info, or want me to try anything else?
Oh, forgot to include the specific processor info in my previous
email:
CPU: AMD Opteron(tm) Processor 4228 HE (2800.05-MHz K8-class CPU)
Origin = "AuthenticAMD" Id = 0x600f12 Family = 0x15 Model = 0x1 Stepping = 2
Features=0x178bfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,MMX,FXSR,SSE,SSE2,HTT>
Features2=0x1e98220b<SSE3,PCLMULQDQ,MON,SSSE3,CX16,SSE4.1,SSE4.2,POPCNT,AESNI,XSAVE,OSXSAVE,AVX>
AMD Features=0x2e500800<SYSCALL,NX,MMX+,FFXSR,Page1GB,RDTSCP,LM>
AMD Features2=0x1c9bfff<LAHF,CMP,SVM,ExtAPIC,CR8,ABM,SSE4A,MAS,Prefetch,OSVW,IBS,XOP,SKINIT,WDT,LWP,FMA4,NodeId,Topology,<b23>,<b24>>
TSC: P-state invariant, performance statistics
--
John-Mark Gurney Voice: +1 415 225 5579
"All that I will do, has been done, All that I have, has not."
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