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SubjectRE: X9SCM-F-O clock drift +1 second into the future when ntp running?
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-----Original Message-----
From: Justin Piszcz [mailto:jpiszcz@lucidpixels.com]
Sent: Saturday, July 07, 2012 11:12 AM
To: pool@lists.ntp.org; linux-kernel@vger.kernel.org
Subject: X9SCM-F-O clock drift +1 second into the future when ntp running?

Hello,

I migrated from an X7SPA to an X9SCM-F-O and now gpsd/ntp no longer sync
with my GPS unit:
http://www.amazon.com/GlobalSat-BU-353-USB-GPS-Receiver/dp/B000PKX2KA

I did some digging and it looks like the system clock on this motherboard
with the latest BIOS (2.00a) runs 1 second too fast when comparing to other
NTP-synchronized machines.

--

I've done some more reading and what I've found is anything over 500ppm ntp
cannot correct for; so is this would be a bad crystal/chip or is there
something else wrong here?

Supermicro X9SCM: (see the error_ppm) is all over the map:

# adjtimex -a
--- current --- -- suggested --
cmos time system-cmos error_ppm tick freq tick freq
1341688282 -0.731743
1341688292 -0.731619 12.4 9993 3497075
1341688302 -0.747186 -1556.7 9993 3497075 10009 659788
1341688312 -0.747117 6.9 9993 3497075 9993 3045513
1341688322 -0.747099 1.8 9993 3497075 9993 3378325
1341688332 -0.762636 -1553.7 9993 3378325 10009 344163
1341688342 -0.762650 -1.4 9993 3378325 9993 3470512
1341688352 -0.778221 -1557.1 9993 3378325 10009 566038

# adjtimex -a
--- current --- -- suggested --
cmos time system-cmos error_ppm tick freq tick freq
1341688564 -0.591964
1341688574 -0.575373 1659.1 10009 566038
1341688584 -0.574515 85.8 10009 566038 10008 1497763
1341688594 -0.558007 1650.8 10009 566038 9992 3789738
1341688604 -0.537084 2092.3 10009 566038 9988 1071325
1341688614 -0.568492 -3140.8 9988 1071325 10019 3744100
1341688624 -0.568774 -28.2 9988 1071325 9988 2919762
1341688634 -0.584618 -1584.4 9988 1071325 10004 49663

Old MSI motherboard (Pentium 4-- see how the PPM is roughly in the same
range)

# adjtimex -a
WARNING: CMOS time is 30.02 min ahead of system clock
--- current --- -- suggested --
cmos time system-cmos error_ppm tick freq tick freq
1341690163 -1800.416735
1341690173 -1800.417111 -37.6 9996 2365500
1341690183 -1800.417499 -38.7 9996 2365500 9996 4904456
1341690193 -1800.417894 -39.5 9996 2365500 9996 4956019
1341690203 -1800.418297 -40.3 9996 2365500 9996 5007582
1341690213 -1800.418308 -1.0 9996 5007582 9996 5074664
1341690223 -1800.418327 -1.9 9996 5007582 9996 5134039
1341690233 -1800.418353 -2.6 9996 5007582 9996 5179351

Found this:
http://compgroups.net/comp.protocols.time.ntp/hopelessly-broken-clock/490495

set clocksource=hpet for boot options instead of TSC

Did not make any difference, still all over the map:

# adjtimex -a
--- current --- -- suggested --
cmos time system-cmos error_ppm tick freq tick freq
1341690087 0.238485
1341690097 0.240449 196.4 10015 1475154
1341690107 0.257408 1695.9 10015 1475154 9998 1744166
1341690117 0.274176 1676.8 10015 1475154 9998 2995729
1341690127 0.290927 1675.1 10015 1475154 9998 3106666
1341690137 0.291142 21.5 9998 3106666 9998 1697291
1341690147 0.275783 -1535.9 9998 3106666 10013 5458916
1341690157 0.276029 24.6 9998 3106666 9998 1494166

Has anyone seen anything like this before?
I checked all of the BIOS options, did not see anything out of the ordinary
here..

Justin.



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