unruh wrote:
On 2011-09-19, David Lord <[email protected]> wrote:
Miguel Gon?alves wrote:
Hi all!
I am having a problem with a Dell server that has a Garmin 18 LVC attached.
It's a FreeBSD 7.4 machine with the Garmin 18 LVC connected to a serial port
(PPS on DCD pin). The kernel has been compiled with the line "OPTIONS
PPS_SYNC". NTP is 4.2.4p5.
Here's the ntp.conf file:
server 127.127.20.0 mode 2 iburst prefer
fudge 127.127.20.0 flag3 1
server ntp-p1.obspm.fr iburst
server ptbtime1.ptb.de iburst
server ntp.inrim.it iburst
server ntp1.oma.be iburst
server canon.inria.fr iburst
server time.fu-berlin.de iburst
server chronos.csr.net iburst
server ntp1.nl.uu.net iburst
statsdir /var/log/ntp/
filegen clockstats file clockstats type day enable
filegen peerstats file peerstats type day enable
filegen loopstats file loopstats type day enable
statistics clockstats peerstats loopstats
logfile /var/log/ntp/messages
restrict default kod nomodify notrap nopeer
restrict 127.0.0.1
I've disabled ACPI in /boot/loader.conf (hint.acpi.0.disabled=1) but did not
disable serial FIFO.
I am getting very high offsets and jitter for this reference clock:
remote refid st t when poll reach delay offset
jitter
==============================================================================
*GPS_NMEA(0) .GPS. 0 l 40 64 377 0.000 -0.031
0.043
+ntp-p1.obspm.fr .TS-3. 1 u 50 64 377 54.154 1.611
1.843
-ptbtime1.ptb.de .DCFa. 1 u 119 64 376 70.069 -2.174
1.283
-ntp.ien.it .CTD. 1 u 35 64 377 65.682 2.037
6.667
-ntp1.oma.be .PPS. 1 u 26 64 377 61.911 2.280
3.673
+canon.inria.fr .GPSi. 1 u 30 64 377 54.626 1.442
1.700
-time.fu-berlin. .PPS. 1 u 32 64 377 73.342 -0.292
3.136
-chronos.csr.net .GPS. 1 u 32 64 377 85.049 -3.656
5.096
-ntp1.nl.uu.net .PPS. 1 u 2 64 377 67.085 3.435
3.888
tick# ntpdc -c kerninfo
pll offset: -7.886e-06 s
pll frequency: -6.729 ppm
maximum error: 0.030005 s
estimated error: 6e-06 s
status: 2107 pll ppsfreq ppstime ppssignal nano
pll time constant: 6
precision: 1e-09 s
frequency tolerance: 496 ppm
pps frequency: -6.729 ppm
pps stability: 0.312 ppm
pps jitter: 4.03e-07 s
calibration interval: 256 s
calibration cycles: 152
jitter exceeded: 1029
stability exceeded: 0
calibration errors: 3
It seems the internal clock of the machine is going nuts (small snippet of
loopstats file):
55822 70649.300 0.000037529 -6.306 0.000000816 0.139388 6
55822 70714.307 0.000004089 -6.175 0.000001464 0.138376 6
55822 70779.307 -0.000029839 -6.175 0.000013699 0.129439 6
55822 70845.306 -0.000058655 -6.175 0.000000562 0.121079 6
55822 70909.305 -0.000078382 -6.175 0.000000570 0.113259 6
55822 70972.305 -0.000061801 -6.729 0.000001320 0.222533 6
55822 71035.304 -0.000041884 -6.729 0.000000778 0.208161 6
55822 71100.304 -0.000023847 -6.729 0.000000629 0.194717 6
55822 71166.303 -0.000003148 -6.595 0.000001515 0.188165 6
55822 71232.302 0.000006531 -6.595 0.000004666 0.176012 6
NetBSD-5, ntpd 4.2.6p3
My time sync has blipped twice each evening at times when
system load is high during log creation/rotation. Mostly
I don't notice. Currently I'm using a Sure-Electronics
but my Garmin 18x-LVC was the same. Blips are from < 15u
up to over 40u.
Clearly a problem with interrupt processing then. the interrupt is being
delayed (disk activity? ) by many us by something.
I didn't see it as a problem, but whatever, I'll continue
to live with it.
David
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