[ntp:questions] Second attempt at GPS-18 based NTP server

Kenyon Ralph kenyon at kenyonralph.com
Wed Feb 8 19:22:13 UTC 2012


On 2012-02-03T15:55:41-0000, David J Taylor <david-taylor at blueyonder.co.uk.invalid> wrote:
> >The need to make a custom kernel that includes option PPS_SYNC is
> >still true on the recently released FreeBSD 9.0.
> >
> >Tom
> 
> Thanks, Tom.  I'm not familiar with FreeBSD 8.0, but looking at the
> revision dates on some files it appears that I /may/ have recompiled
> the kernel.  Difficult for me to tell, though.  This is what I see:
> 
> ______________________________
> C:\>ntpdc -c kerninfo pixie
> pll offset:           -0.00234 s
> pll frequency:        27.835 ppm
> maximum error:        0.008483 s
> estimated error:      2e-006 s
> status:               2107
> pll time constant:    4
> precision:            1e-006 s
> frequency tolerance:  496 ppm
> pps frequency:        27.835 ppm
> pps stability:        0.007 ppm
> pps jitter:           0.00274 s
> calibration interval: 256 s
> calibration cycles:   160784
> jitter exceeded:      30488
> stability exceeded:   0
> calibration errors:   11
> ______________________________
> 
> C:\>ntpq -p pixie
>     remote           refid      st t when poll reach   delay
> offset jitter
> ==============================================================================
> *GPS_NMEA(1)     .PPS.            0 l    6   16  377    0.000
> 0.001 0.004
> -odie.tomelliott 158.43.128.33    2 u  746 1024  377   23.658
> 3.961 7.972
> -dnscache-london 140.203.204.77   2 u  845 1024  377   27.784
> 0.433 18.409
> 195.66.148.150  140.203.204.77   2 u 370d 1024    0   25.383
> 3.955 0.000
> ______________________________
> 
> 
> so perhaps I did.  I don't see the "o" of the Atom driver, though.

I don't think you're using the kernel PPS signal, so you may not have
compiled the kernel with the PPS_SYNC option. This is what you should
see, notice the "o" and mentions of PPS in kerninfo output (this
output is from my system at gauss.kenyonralph.com):

% ntpq -p -c clockvar -c readvar -c kerninfo
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
oGPS_NMEA(0)     .GPS.            0 l    2    8  377    0.000    0.000   0.001
+darwin.kenyonra 127.67.113.92    2 u   44   64  377   21.390    2.368   2.346
 voodoo.kenyonra 94.78.119.192    2 u   42   64  377    0.266   -0.049   0.101
 grunt.kenyonral 94.78.119.192    2 u   23   64  377    0.177    0.338   0.137
+clock.fmt.he.ne .CDMA.           1 u   52   64  377   21.849    2.738   4.929
*tick.ucla.edu   .GPS.            1 u    5   64  377   31.669    2.297   2.449
+2607:fa18::2407 .GPS.            1 u   26   64  377   42.877    2.162   2.844
+ntp.exact-time. .GPS.            1 u   53   64  377  204.112    0.845   4.218
+ntp.your.org    .CDMA.           1 u   39   64  377   73.350    1.922   3.373
-otc2.psu.edu    189.122.110.167  2 u   26   64  377  104.273    4.057   5.620
+ntp2.jtsage.com 127.67.113.92    2 u   33   64  377   60.318    0.887   1.376
+tick.e.mattnord 129.7.1.66       2 u   56   64  377   60.775    0.466   1.532
associd=0 status=0000 no events, clk_unspec,
device="NMEA GPS Clock",
timecode="$GPGGA,191413,3259.1559,N,11714.2879,W,1,07,1.6,126.8,M,-35.3,M,,*79",
poll=48532, noreply=0, badformat=0, baddata=0, fudgetime2=600.000,
stratum=0, refid=GPS, flags=5
associd=0 status=0415 leap_none, sync_uhf_radio, 1 event, clock_sync,
version="ntpd 4.2.7p255 at 1.2483-o Sat Feb  4 07:17:31 UTC 2012 (1)",
processor="amd64", system="FreeBSD/9.0-STABLE", leap=00, stratum=1,
precision=-20, rootdelay=0.000, rootdisp=1.060, refid=GPS,
reftime=d2dd4801.c5aa4064  Wed, Feb  8 2012 11:14:09.772,
clock=d2dd4806.88e99e3f  Wed, Feb  8 2012 11:14:14.534, peer=42035, tc=3,
mintc=3, offset=-0.000, frequency=-4.149, sys_jitter=0.001,
clk_jitter=0.001, clk_wander=0.001
associd=0 status=0415 leap_none, sync_uhf_radio, 1 event, clock_sync,
pll offset:            -0.002731
pll frequency:         -4.14865
maximum error:         0.0035
estimated error:       0
kernel status:         pll ppsfreq ppstime ppssignal nano
pll time constant:     3
precision:             1e-06
frequency tolerance:   495.911
pps frequency:         -4.14865
pps stability:         0.00845337
pps jitter:            0.002
calibration interval   256
calibration cycles:    3295
jitter exceeded:       14137
stability exceeded:    0
calibration errors:    8

-- 
Kenyon Ralph
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