On Tue, Jan 25, 2022 at 11:29:04AM -0500, Charlie Laub wrote: > Hello Miroslav, > > Thank you for creating and publishing this new page. The info is very > helpful and demonstrates the level of accuracy that can be achieved under a > variety of configurations. I have a local GPS PPS based (via NTP running on > an R-Pi) Stratum 1 server. The other machines on my network all run chrony > and reach tens of microseconds error, which is OK but could be better. I > need to synchronize them in order to coordinate distributed audio playback, > for which 1msec is too much error between machines. But synchronicity better > than 100 usec works OK, with 10 usec being the ultimate goal. I will look at > your examples to see how I can improve the client performance, however, most > machines (not the stratum 1 server) are WiFi based so I doubt I can improve > them much more. My clients use a poll interval of 4 or 5 for the GPS based > local timeserver. No PTP or hardware timestamping is used.
Getting wireless clients within 10 microseconds is going to be very difficult. The drivers don't even provide a software TX timestamp. You could try a shorter polling interval combined with the maxdelay and burst options. You would need to find the minimum peer delay for each device at which it can get a good measurement frequently enough to keep the clock in sync. This assumes the network is not loaded for longer periods of time. For example: server ntp.local minpoll 0 maxpoll 2 burst maxdelay 0.0012 xleave How do you verify that the clients are in sync? I assume they work as speakers. Is there a tool which can analyse recorded audio of multiple speakers and tell you how well they agree with one another? -- 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.