[ntp:questions] ntp_adjtime() in linux 2.4.21-NANO

Bjorn Gabrielsson bg at lysator.liu.se
Thu Feb 5 00:13:40 UTC 2004


It seems to me that some data in ntp_adjtime() is 1000 times larger
than it should be - offset, jitter and precision. The nano-kernel(?)
also fill the logs with (mostly) complaints of excessive jitter.

Is this related?

br,
        Björn 

--- some data---- 
 #/usr/sbin/ntpq -c pe                         
       
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
 LOCAL(0)        LOCAL(0)        10 l   54   64  377    0.000    0.000   0.001
*GPS_JUPITER(0)  .GPS.            0 l    3   16  377    0.000    0.001   0.001
 perrin          xxx.xxx.xxx.xx   2 u   22   32  377    0.202   -0.228   0.053
+ntp1.no.where   .PPS.            1 u   43   64  377   20.746   -0.531   0.700
+ntp2.no.where   .PPS.            1 u   62   64  377   12.653    0.099   0.255
+ntp3.no.where   .PPS.            1 u    -   64  377   12.479    0.119   0.139
 
#ntptime

ntp_gettime() returns code 0 (OK)
  time c3cc063e.4b791000  Thu, Feb  5 2004  1:01:02.294, (.656703392),
  maximum error 764 us, estimated error 1 us
ntp_adjtime() returns code 0 (OK)
  modes 0x0 (),
  offset 928.000 us, frequency 18.343 ppm, interval 256 s,
  maximum error 764 us, estimated error 1 us,
  status 0x2107 (PLL,PPSFREQ,PPSTIME,PPSSIGNAL,NANO),
  time constant 4, precision 576.000 us, tolerance 496 ppm,
  pps frequency 18.343 ppm, stability 0.014 ppm, jitter 5846.000 us,
  intervals 3434, jitter exceeded 34958, stability exceeded 213, errors 0.

#dmesg
...
hardpps: PPSTIME monitor=224, jitter=2193
hardpps: PPSTIME monitor=160, jitter=1740
hardpps: PPSTIME monitor=160, jitter=1329
hardpps: PPSTIME monitor=160, jitter=1020
hardpps: PPSTIME monitor=128, jitter=781
hardpps: PPSTIME monitor=192, jitter=745
hardpps: PPSTIME monitor=-448, jitter=726
hardpps: PPSTIME monitor=-96, jitter=1096
hardpps: PPSTIME monitor=-96, jitter=1374
hardpps: PPSTIME monitor=128, jitter=1590
hardpps: PPSTIME monitor=128, jitter=1280
...

# ntpq -c ver
ntpq 4.2.0 at 1.1161-r Wed Oct 15 23:02:34 CEST 2003 (1)



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