[ntp:questions] System time ramps forcing step correction?

A C agcarver+ntp at acarver.net
Sun Sep 9 22:07:49 UTC 2012


Has anyone seen a system with GPS/PPS have its system time ramp/slew 
ahead by over a second requiring a step correction?

My system has done it a few times now but it occurs randomly.  Nothing 
seems to be running at that point to bog the system down, but it 
steadily ramps up and then forces a step.  After the step correction it 
runs fine again without restarting anything.

The main log and peers log are included below for the relevant period. 
Everything is otherwise in working order.  I had offsets on the PPS 
signal of less than 50 us for days on end and then over several polling 
periods it suddenly slides up.  After the reset and settling time it 
once again shows 50 us or better offsets.

Sep  9 14:43:48 ntpd[15927]: 0.0.0.0 0113 03 spike_detect +0.199468 s
Sep  9 14:44:36 ntpd[15927]: SHM(0) 961a 8a sys_peer
Sep  9 14:48:36 ntpd[15927]: 0.0.0.0 041c 0c clock_step +1.637940 s
Sep  9 14:48:37 ntpd[15927]: 0.0.0.0 0415 05 clock_sync
Sep  9 14:48:38 ntpd[15927]: 0.0.0.0 c418 08 no_sys_peer
Sep  9 14:48:39 ntpd[15927]: 130.207.165.28 8074 84 reachable
Sep  9 14:48:41 ntpd[15927]: 64.73.32.134 8014 84 reachable
Sep  9 14:48:46 ntpd[15927]: 199.195.157.129 8014 84 reachable
Sep  9 14:48:47 ntpd[15927]: 131.144.4.10 8014 84 reachable
Sep  9 14:48:48 ntpd[15927]: 173.244.211.10 8014 84 reachable
Sep  9 14:48:54 ntpd[15927]: SHM(0) 8024 84 reachable
Sep  9 14:48:55 ntpd[15927]: SHM(0) 903a 8a sys_peer
Sep  9 14:48:55 ntpd[15927]: PPS(0) 80f4 84 reachable


  56179 52964.205 127.127.28.0    96aa -0.001955500  0.000000000 
0.001009236  0.006310839
  56179 52964.299 127.127.22.0    97ea  0.000021424  0.000000000 
0.000353156  0.000122070
  56179 52980.210 127.127.28.0    96aa -0.005907500  0.000000000 
0.000934828  0.006095279
  56179 52980.223 127.127.22.0    97ea  0.000021397  0.000000000 
0.000353156  0.000122070
  56179 52996.212 127.127.28.0    96aa  0.025111400  0.000000000 
0.003454317  0.027811839
  56179 52996.260 127.127.22.0    97ea  0.017741486  0.000000000 
0.002494002  0.017720290
  56179 53012.218 127.127.28.0    96aa  0.101122500  0.000000000 
0.004629340  0.100438971
  56179 53012.254 127.127.22.0    97ea  0.115746997  0.000000000 
0.003698620  0.113364049
  56179 53027.331 131.144.4.10    9414  0.219849847  0.098492987 
0.015403803  0.223524435
  56179 53028.262 127.127.28.0    96aa  0.183939100  0.000000000 
0.004767848  0.171374122
  56179 53028.362 127.127.22.0    97ea  0.199467822  0.000000000 
0.004300935  0.184750100
  56179 53044.177 127.127.28.0    96aa  0.266197900  0.000000000 
0.006370305  0.232862585
  56179 53044.260 127.127.22.0    97ea  0.278265812  0.000000000 
0.004600780  0.242066773
  56179 53057.283 173.244.211.10  9414  0.365689759  0.055636674 
0.015279464  0.369880622
  56179 53057.465 64.73.32.134    9414  0.367759156  0.088845233 
0.015650399  0.370900106
  56179 53060.204 127.127.28.0    96aa  0.334443800  0.000000000 
0.005366910  0.271473247
  56179 53060.508 127.127.22.0    97ea  0.361990616  0.000000000 
0.004751800  0.294141014
  56179 53076.209 127.127.28.0    96aa  0.408916700  0.000000000 
0.005999364  0.306936161
  56179 53076.486 127.127.22.0    91ea  0.426011446  0.000000000 
0.004827480  0.316934617
  56179 53092.278 127.127.28.0    961a  0.482537200  0.000000000 
0.006837707  0.328765855
  56179 53092.365 127.127.22.0    91ea -0.383371184  0.000000000 
0.148976255  0.602984184
  56179 53108.250 127.127.28.0    961a  0.544067000  0.000000000 
0.011001864  0.324788171
  56179 53108.295 127.127.22.0    91ea -0.416390385  0.000000000 
0.076939537  0.615290563
  56179 53124.211 127.127.28.0    961a  0.649968778  0.000000000 
0.008918378  0.351040620
  56179 53124.329 127.127.22.0    91ea -0.322817225  0.000000000 
0.040912920  0.516658210
  56179 53140.213 127.127.28.0    961a  0.722892500  0.000000000 
0.007316460  0.347147770
  56179 53140.315 127.127.22.0    91ea -0.244019932  0.000000000 
0.022898930  0.437687751
  56179 53156.212 127.127.28.0    961a  0.824011900  0.000000000 
0.007386004  0.370063251
  56179 53156.312 127.127.22.0    91ea -0.194288208  0.000000000 
0.014254929  0.382024643
  56179 53172.216 127.127.28.0    961a  0.908267000  0.000000000 
0.007305088  0.378095205
  56179 53172.252 127.127.22.0    91ea -0.086424350  0.000000000 
0.009570471  0.327996952
  56179 53188.189 127.127.28.0    961a  0.976407100  0.000000000 
0.007665880  0.368698443
  56179 53188.272 127.127.22.0    91ea -0.017477303  0.000000000 
0.007228234  0.309437756
  56179 53204.209 127.127.28.0    961a  1.074038100  0.000000000 
0.006528834  0.384225692
  56179 53204.305 127.127.22.0    91ea  0.066250487  0.000000000 
0.006056954  0.334011042
  56179 53220.208 127.127.28.0    961a  1.178942500  0.000000000 
0.008416913  0.403932134
  56179 53220.301 127.127.22.0    91ea  0.140124349  0.000000000 
0.004908276  0.351535830
  56179 53236.212 127.127.28.0    961a  1.234154100  0.000000000 
0.006697357  0.372673528
  56179 53236.301 127.127.22.0    91ea  0.228771490  0.000000000 
0.004897344  0.358771640
  56179 53252.223 127.127.28.0    961a  1.313991200  0.000000000 
0.006395539  0.368441145
  56179 53252.327 127.127.22.0    91ea  0.307569878  0.000000000 
0.004890305  0.360452537
  56179 53255.354 130.207.165.28  946a  1.347350879  0.094996301 
0.015541740  1.353118110
  56179 53268.211 127.127.28.0    961a  1.380825600  0.000000000 
0.006780171  0.350053500
  56179 53268.403 127.127.22.0    91ea  0.391294185  0.000000000 
0.004888043  0.366524009
  56179 53284.240 127.127.28.0    961a  1.448494889  0.000000000 
0.006228365  0.337258226
  56179 53284.324 127.127.22.0    91ea  0.455309940  0.000000000 
0.004885399  0.347430948
  56179 53300.234 127.127.28.0    961a  1.524304800  0.000000000 
0.005397721  0.333158000
  56179 53300.318 127.127.22.0    91ea -0.451111626  0.000000000 
0.004885168  0.694298057
  56179 53316.224 127.127.28.0    961a  1.637940250  0.000000000 
0.008713945  0.360864303
  56179 53319.210 130.207.165.28  9074  0.016513612  0.093000608 
7.937562209  0.000122070
  56179 53321.162 64.73.32.134    9014  0.017817437  0.090057767 
7.937561949  0.000122070
  56179 53326.163 199.195.157.129 9014  0.019706601  0.105027265 
7.937561942  0.000122070
  56179 53327.142 131.144.4.10    9014  0.018367416  0.097738834 
7.937562245  0.000122070
  56179 53328.129 173.244.211.10  9014  0.015613556  0.055379973 
7.937561689  0.000122070
  56179 53335.054 127.127.28.0    9024  0.021529900  0.000000000 
7.938050903  0.000122070
  56179 53336.000 127.127.22.0    90f4 -0.034798745  0.000000000 
7.978560157  0.000122070
  56179 53350.986 127.127.28.0    963a  0.024048700  0.000000000 
3.938475362  0.002518800
  56179 53351.998 127.127.22.0    97f4  0.023017031  0.000000000 
3.958152962  0.057815776


More information about the questions mailing list