[Soekris] severe clock drift on net6501

David Mansfield soekris at dm.cobite.com
Tue Sep 10 16:19:44 CEST 2013


Hi All,

I'm just completing the OS install (centos 6.4) on a new net6501.

After getting NTP setup, I noticed it wouldn't ever synchronize, and 
every 15 1/2 minutes, a large adjustment would be made to the system clock:

Sep  9 10:12:54 hadrian ntpd[3452]: time reset -0.626500 s
Sep  9 10:28:20 hadrian ntpd[3452]: time reset -0.643714 s
Sep  9 10:43:29 hadrian ntpd[3452]: time reset -0.606849 s
Sep  9 10:58:45 hadrian ntpd[3452]: time reset -0.633372 s

Fairly consistently .6 seconds every 15 1/2 minutes or so.  I'm 
wondering if this is indicative of faulty hardware?

I have a workaround:

After reading around, I used adjtimex to determine an adjustment to the 
kernel parameters, and ran this:

adjtimex --tick 9987  --freq 3533487

Now NTP is happy and has synchronized the system clock.

FYI:

cat /sys/devices/system/clocksource/clocksource0/current_clocksource

shows:

jiffies

and:

cat /sys/devices/system/clocksource/clocksource0/available_clocksource

shows:

jiffies tsc

-- 
Thanks,
David Mansfield
Cobite, INC.



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