[ntp:questions] question about logs of PPS

Christian Pinedo Zamalloa christian.pinedo.zamalloaNOSPAM at NOKKgmail.com
Wed May 9 11:38:10 UTC 2007


hi all,

I'm a newbiew on NTP services, but anyway I'm trying to setup a Stratum1
server with the following hardware and software:

- GPS Motorola Oncore M12
- Server:
    - CentOS 3.8
    - Linux kernel 2.4.33.3
    - ntp 4.2.2p4
    - PPSKit 2.1.7

I have configured the /etc/ntp.conf and /etc/ntp.oncore0 files and all
seems good but the logs. In the /var/log/messages i see after several
hours I started the NTPD daemon:

May  9 13:29:07 khronos sshd(pam_unix)[1052]: session opened for user
jtbpizac by (uid=0)
May  9 13:29:07 khronos kernel: hardpps: PPSJITTER: jitter=330839,
limit=13208
May  9 13:29:13 khronos kernel: hardpps: new frequency -217491 >> 4 ==
-13594
May  9 13:29:13 khronos kernel: hardpps: new pps.freq=-13593 (add 37)
May  9 13:29:20 khronos su(pam_unix)[1096]: session opened for user root
by jtbpizac(uid=501)
May  9 13:29:29 khronos kernel: hardpps: new frequency -217098 >> 4 ==
-13569
May  9 13:29:29 khronos kernel: hardpps: new pps.freq=-13568 (add 24)
May  9 13:29:37 khronos kernel: hardpps: PPSJITTER: jitter=334175,
limit=10732
May  9 13:29:45 khronos kernel: hardpps: new frequency -216445 >> 4 ==
-13528
May  9 13:29:45 khronos kernel: hardpps: new pps.freq=-13527 (add 40)
May  9 13:30:07 khronos kernel: hardpps: PPSJITTER: jitter=294411,
limit=4864
May  9 13:30:09 khronos kernel: hardpps: PPSJITTER: jitter=302386,
limit=298056
May  9 13:30:17 khronos kernel: hardpps: new frequency -434869 >> 5 ==
-13590
May  9 13:30:17 khronos kernel: hardpps: new pps.freq=-13589 (add -61)
May  9 13:30:37 khronos kernel: hardpps: PPSJITTER: jitter=290707,
limit=6260
May  9 13:30:39 khronos kernel: hardpps: PPSJITTER: jitter=303013,
limit=295400
May  9 13:30:49 khronos kernel: hardpps: new frequency -434859 >> 5 ==
-13590
May  9 13:30:49 khronos kernel: hardpps: new pps.freq=-13589 (add 0)
May  9 13:31:07 khronos kernel: hardpps: PPSJITTER: jitter=327983,
limit=4232
May  9 13:31:21 khronos kernel: hardpps: new frequency -433636 >> 5 ==
-13552
May  9 13:31:21 khronos kernel: hardpps: new pps.freq=-13551 (add 38)
May  9 13:31:37 khronos kernel: hardpps: PPSJITTER: jitter=327881,
limit=3332
May  9 13:31:53 khronos kernel: hardpps: new frequency -434615 >> 5 ==
-13582
May  9 13:31:53 khronos kernel: hardpps: new pps.freq=-13581 (add -30)
May  9 13:32:07 khronos kernel: hardpps: PPSJITTER: jitter=323754,
limit=3620
May  9 13:32:37 khronos kernel: hardpps: PPSJITTER: jitter=322598,
limit=4844
May  9 13:32:57 khronos kernel: hardpps: new frequency -870709 >> 6 ==
-13605
May  9 13:32:57 khronos kernel: hardpps: new pps.freq=-13604 (add -23)
May  9 13:33:07 khronos kernel: hardpps: PPSJITTER: jitter=319882,
limit=5772
May  9 13:33:37 khronos kernel: hardpps: PPSJITTER: jitter=319118,
limit=314

And sometimes it appears:

May  9 13:27:55 khronos kernel: hardpps: PPSJITTER: jitter=98335,
limit=14772
May  9 13:28:07 khronos kernel: hardpps: bad pulse, delta = -794324 ns
May  9 13:28:08 khronos kernel: hardpps: bad pulse, delta = 769390 ns
May  9 13:28:09 khronos kernel: hardpps: PPSJITTER: jitter=841424,
limit=177076

Is this the normal behavour or are the constants frequency changes a
signal that something could be misconfigured?

Thanks a lot,

Christian




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