[LinuxPPS] ntptime status - relaunch of that issue

[William S. Brasher]

On Tue, 17 Feb 2009, Felix Joussein wrote:

> Hello list,
> 
> 
> The  status 0x2107 (PLL,PPSFREQ,PPSTIME,PPSSIGNAL,NANO) is different.
> 
> What makes the difference, at which part of the howto from
> http://wiki.enneenne.com/index.php/LinuxPPS_installation
> might I have not followed correctly?
> 
> Thank you for your help,
> 
> Felix
> 


The status of the PPS flags - PPSFREQ, PPSTIME, PPSSIGNAL, PPSJITTER - is 
that they are set to 0 in the kernel.

See kernel/time/ntp.c which has a comment in do_adjtimex() 
/* PPS is not implemented, so these are zero */ just before the pps stuff 
is set to 0 and the function returns.

For what it's worth, I've attached some data from my 2.6 kernel based PPS 
clock below.  I am using the pps driver, 127.127.22.x, and ntp was patched 
with the nmea patch.


Bill




bill at tara: $ ntpq -p
     remote           refid      st t when poll reach   delay   offset  
jitter
==============================================================================
+GPS_NMEA(0)     .GPS.            0 l   14   16  377    0.000   -0.001   0.002
oPPS(0)          .PPS.            0 l   12   16  377    0.000   -0.001   0.002
-chronos.q.lan   .PPS.            1 u   25   64  377    0.195    0.019   0.005
-tick.q.lan      .PPS.            1 u   11   64  377    0.150    0.014   0.006
+tock.q.lan      .PPS.            1 u   28   64  377    0.156    0.003   0.009
 frodo.q.lan     192.168.48.2     2 u   51   64  377    0.202    0.222   0.036
 merlin.q.lan    192.168.48.2     2 u   56   64  377    0.196   -0.381   0.011
 gandalf.q.lan   192.168.48.2     2 u   25   64  377    0.173    0.125   0.022
 alpha.q.lan     192.168.48.19    2 u   24   64  377    0.211    0.038   0.010


bill at tara: $ ntptime
ntp_gettime() returns code 0 (OK)
  time cd4552eb.85439db4  Tue, Feb 17 2009  9:14:51.520, (.520563035),
  maximum error 5981 us, estimated error 1 us, TAI offset 34
ntp_adjtime() returns code 0 (OK)
  modes 0x0 (),
  offset -0.721 us, frequency 2.295 ppm, interval 1 s,
  maximum error 5981 us, estimated error 1 us,
  status 0x2001 (PLL,NANO),
  time constant 4, precision 0.001 us, tolerance 500 ppm,


bill at tara: $ ntpq -c rv
assID=0 status=21f4 leap_none, sync_atomic/PPS, 15 events, 
event_peer/strat_chg,
version="ntpd 4.2.4p6 at 1.1549-o Sat Jan 10 23:29:35 UTC 2009 (1)",
processor="i686", system="Linux/2.6.28-pps", leap=00, stratum=1,
precision=-19, rootdelay=0.000, rootdispersion=0.260, peer=54484,
refid=PPS, reftime=cd4552f1.46dfcc36  Tue, Feb 17 2009  9:14:57.276,
poll=4, clock=cd4552f3.41935cda  Tue, Feb 17 2009  9:14:59.256, state=4,
offset=-0.001, frequency=2.295, jitter=0.002, noise=0.002,
stability=0.000, hostname="tara", signature="md5WithRSAEncryption",
flags=0x80003, update=200902171206, leapsec=200808080000, tai=34,
cert="tara tara 0x0", expire=200912151950
bill at tara: $