Well, I loaded Debian 8.2 on one of my BBB's, and then did a cold start and you can see the following in syslog. timesyncd starts off at a 32 second sntp resync with the server, then moves up in powers of two to a maximum sync time of about 34 minutes.
You can see it is making only single digit millisecond corrections to the system clock, once it converges. This BBB has had the caps across the master crystal changed to get the master clock error down into the single digit ppm. Most of the factory BBB's are in the 50 to 70 ppm error range. Dec 9 18:28:49 beaglebone systemd-timesyncd[220]: Using NTP server 66.135.44.92:123 (2.debian.pool.ntp.org). Dec 9 18:28:49 beaglebone systemd-timesyncd[220]: interval/delta/delay/jitter/drift 32s/-0.182s/0.030s/0.000s/+0ppm Dec 9 18:29:21 beaglebone systemd-timesyncd[220]: interval/delta/delay/jitter/drift 64s/-0.001s/0.031s/0.000s/-7ppm Dec 9 18:30:25 beaglebone systemd-timesyncd[220]: interval/delta/delay/jitter/drift 128s/+0.002s/0.033s/0.001s/+0ppm Dec 9 18:32:33 beaglebone systemd-timesyncd[220]: interval/delta/delay/jitter/drift 256s/-0.001s/0.032s/0.001s/-1ppm Dec 9 18:36:49 beaglebone systemd-timesyncd[220]: interval/delta/delay/jitter/drift 512s/-0.000s/0.030s/0.001s/-1ppm Dec 9 18:45:22 beaglebone systemd-timesyncd[220]: interval/delta/delay/jitter/drift 1024s/-0.004s/0.036s/0.002s/-1ppm (ignored) Dec 9 19:02:26 beaglebone systemd-timesyncd[220]: interval/delta/delay/jitter/drift 2048s/+0.001s/0.026s/0.002s/-1ppm (ignored) Dec 9 19:36:34 beaglebone systemd-timesyncd[220]: interval/delta/delay/jitter/drift 2048s/+0.007s/0.037s/0.003s/+0ppm Dec 9 20:10:42 beaglebone systemd-timesyncd[220]: interval/delta/delay/jitter/drift 2048s/-0.000s/0.038s/0.003s/+0ppm Dec 9 20:44:51 beaglebone systemd-timesyncd[220]: interval/delta/delay/jitter/drift 2048s/-0.003s/0.042s/0.003s/+0ppm The major source of time error is any asymetry in the inbound and outbound path to the ntp server. (Common issue with cable modems.) Reporting of this activity disappeared sometime between Debian 8 and Debian 9. Reading the source code for timesyncd suggests it should still be there, as cron.debug messages, but so far, no joy. I'll watch stat /var/lib/systemd/clock to make sure it is running. If anyone knows how to get the detailed timesyncd messages back, I would like to hear about it. --- Graham == -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CAC_N71p9T1%3D%3DramC2opXb7ogswFtP8Scp5y3KdSWXAkVOc7MAQ%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
