On Tue, May 14, 2024 at 04:35:14PM +0530, Abhijith Sethuraj wrote: > > How did you measure that 50us error? Can you use that source of time > > for synchronization? > Unfortunately, we can't use that as a source. This difference is what an > application noticed when it was looking at a timestamp that's there inside > a data packet (think of it as tx timestamp from a server that we don't have > control over) and what's obtained from system clock via gettimeofday() > right when it received the data packet.
Is this server synchronized to the same NTP server as the computer running the client application? What root distance does it report? > Is there anything else that you would recommend we > monitor on our end to catch these issues? Also, if root distance is ~1ms, > does that imply that the value of current time that I get from > gettimeofday() essentially has an error of ~1ms or is this just inferring > to the error in measurements from source (and that the user-space app need > not consider this)? Root distance is an estimate of the maximum error. The actual error is usually much smaller, but if you don't have something more accurate to measure it, you won't know. You need a better server for the application server and client to minimize the maximum error. It needs to be closer to get a smaller root delay and have a better reference clock or better implementation to get a smaller root dispersion. Ideally, it should run chrony with hardware timestamping. -- 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.
