Re: [chrony-users] Syncromisation confusion
On Tue, Mar 23, 2021 at 03:57:56PM +0100, Mattias Winther wrote: > > It sounds like that PHC is not synchronized to anything. Is it > > supposed to be synchronized by ptp4l in a PTP domain? > > Yeah, that is right, it doesn’t sync. I got the impression that the refclock > in pps mode was keeping the tempo, so to speak, and then would use the ntp > server data to get the rest of the timestamp from, but from your question I > get the feeling this is not what PHC pps mode does? In the pps mode it still needs to be synchronized. It just ignores a whole number of seconds in the offset, e.g. due to TAI-UTC mismatch. chronyd cannot use a reference clock for frequency only. I'm not sure if a free-running PHC would be a good frequency reference anyway. -- Miroslav Lichvar -- To unsubscribe email chrony-users-requ...@chrony.tuxfamily.org with "unsubscribe" in the subject. For help email chrony-users-requ...@chrony.tuxfamily.org with "help" in the subject. Trouble? Email listmas...@chrony.tuxfamily.org.
Re: [chrony-users] Syncromisation confusion
> 23 mars 2021 kl. 15:41 skrev Miroslav Lichvar : > > On Tue, Mar 23, 2021 at 03:17:01PM +0100, Mattias Winther wrote: >> I tried adding a refclock PCH in pps mode to my chrony machine, which gets >> its time from an ntpd server running on my firewall, which in turn gets >> it's time from three different ntp.pool.org-servers. At the moment, the >> chrony machine is not talking to any other sources. >> >> Without the refclock, the offset when graphed was fairly shaky, but the >> clock settled in to what seemed to be a consistent sync pattern, albeit >> with a bit less precision than I would like to have. >> >> After the refclock was added, chrony says that it's lacking a majority and >> can't sync for most of the time, and then about every 12 hours it starts to >> sync, spends about 90 minutes speeding up the clock, until all of a sudden >> it stops, and goes right back to not syncing. > > It sounds like that PHC is not synchronized to anything. Is it > supposed to be synchronized by ptp4l in a PTP domain? Yeah, that is right, it doesn’t sync. I got the impression that the refclock in pps mode was keeping the tempo, so to speak, and then would use the ntp server data to get the rest of the timestamp from, but from your question I get the feeling this is not what PHC pps mode does? > -- > Miroslav Lichvar > -- To unsubscribe email chrony-users-requ...@chrony.tuxfamily.org with "unsubscribe" in the subject. For help email chrony-users-requ...@chrony.tuxfamily.org with "help" in the subject. Trouble? Email listmas...@chrony.tuxfamily.org.
Re: [chrony-users] Syncromisation confusion
On Tue, Mar 23, 2021 at 03:17:01PM +0100, Mattias Winther wrote: > I tried adding a refclock PCH in pps mode to my chrony machine, which gets > its time from an ntpd server running on my firewall, which in turn gets > it's time from three different ntp.pool.org-servers. At the moment, the > chrony machine is not talking to any other sources. > > Without the refclock, the offset when graphed was fairly shaky, but the > clock settled in to what seemed to be a consistent sync pattern, albeit > with a bit less precision than I would like to have. > > After the refclock was added, chrony says that it's lacking a majority and > can't sync for most of the time, and then about every 12 hours it starts to > sync, spends about 90 minutes speeding up the clock, until all of a sudden > it stops, and goes right back to not syncing. It sounds like that PHC is not synchronized to anything. Is it supposed to be synchronized by ptp4l in a PTP domain? -- Miroslav Lichvar -- To unsubscribe email chrony-users-requ...@chrony.tuxfamily.org with "unsubscribe" in the subject. For help email chrony-users-requ...@chrony.tuxfamily.org with "help" in the subject. Trouble? Email listmas...@chrony.tuxfamily.org.
[chrony-users] Syncromisation confusion
I tried adding a refclock PCH in pps mode to my chrony machine, which gets its time from an ntpd server running on my firewall, which in turn gets it's time from three different ntp.pool.org-servers. At the moment, the chrony machine is not talking to any other sources. Without the refclock, the offset when graphed was fairly shaky, but the clock settled in to what seemed to be a consistent sync pattern, albeit with a bit less precision than I would like to have. After the refclock was added, chrony says that it's lacking a majority and can't sync for most of the time, and then about every 12 hours it starts to sync, spends about 90 minutes speeding up the clock, until all of a sudden it stops, and goes right back to not syncing. https://cdn.discordapp.com/attachments/821349976999329794/823912884186775572/testing.png (apologies if external links aren't allowed here) shows a graph of the measurement.log output during this time. Even though I don't understand what's going on, I'm fascinated by the behavior. Is there anyone who can help me understand what is happening based on the data in the graph? Is there other data needed to explain and understand what is happening? o/ MW
