On Mon, Mar 2, 2020 at 5:23 PM David J Taylor via time-nuts < [email protected]> wrote:
> Hi! > > For several weeks I'm seeing strange behavior of my Raspberry Pi based NTP > server with Uputronics GPS PPS expansion board (Ublox MAX-M8Q chip). > Several weeks ago the mean daily jitter was below 300 ns, offset didn't > exceed ±1 µs, provided no restart or configuration change was made. Now the > offset often wanders even below 5 µs, steady change, and then comes back. > You can see it at the screenshot from my Grafana server (attached). As you > can see, the number of satellites visible and TDOP value should not be the > cause of it. > > My current ntp.conf is as follows (I use ntpsec and gpsd): > > driftfile /var/lib/ntp/ntp.drift > leapfile /var/lib/ntp/leap-seconds.list > > statsdir /var/log/ntpstats/ > statistics loopstats peerstats > filegen loopstats file loopstats type day enable > filegen peerstats file peerstats type day enable > > restrict default limited kod nomodify nopeer noquery > restrict source nomodify noquery > restrict 127.0.0.1 > restrict 192.168.0.0 mask 255.255.0.0 > > tos mindist 0.002 > > refclock shm unit 1 minpoll 4 maxpoll 4 flag4 1 prefer refid PPS > refclock shm unit 0 minpoll 4 maxpoll 4 time1 0.057984 refid GPS > > #server nts.time.nl nts > #server nts.ntp.se:4443 nts > > server tempus1.gum.gov.pl prefer > server tempus2.gum.gov.pl > server ntp.task.gda.pl > server ntp.nask.pl > > server MY_GPSDO iburst > > Before that I thought it was because I used NTP pool, as some time ago > similar behavior was mentioned here on the list, but, as you can see, I do > not use it anymore and the same strange behavior remained. > > Any idea what could be the cause of this? Thanks in advance. > > Adam > ==================================== > > What are you doing to that poor RPi to drive its CPU up to 66 C! Rather > hot! > > That's the first thing I would investigate if the CPU load is really so > low > (9%). Comparing, my oldest RPi server is a lowly RasPi 1B, and it runs at > 2% CPU, ~43 C CPU (averaged over a day). It lives in an unheated cupboard > on an outside wall. > > Cheers, > David > It's ~65°C on purpose. I'm using ntpheat ( https://blog.ntpsec.org/2017/02/01/heat-it-up.html) to keep stable temperature no matter what it does. It turns my raspberry into kind of OCXO :) Anyway, ntpheat runs there for months, so I guess it's not the culprit. Cheers, Adam _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
