Changed kalman offset message to debug level

[jpds]

After deploying ntpd-rs on my systems, the system logs are peppered with:

ntp-daemon[2022]: 2025-04-28T22:16:44.902268Z  INFO ntp_proto::algorithm::kalman: Offset: -9.71569488420898+-5.958433943105912ms, frequency: -0.029784204729893793+-1.5403756385090928pp

Which isn't useful to the average system admin, hence reduce this message to debug.

[rnijveld]

This is the core functionality of our daemon (i.e. determining what the time and frequency offsets are). I'm not sure what should be an info level log message, if this is not it? If you're not interested in that information, you could also increase the log level to warn or higher?

[rnijveld]

I do think that the messages themselves might a little too spammy though: the formatting isn't great (way to many digits, most of them realistically completely useless information) and the number of messages might be too high especially when you have many sources (even more so with a low max poll interval) given that we get these messages most of the time when we receive a new packet from a source.

[jpds]

I'm interested in this message at info:

ntpd-rs/ntp-proto/src/algorithm/kalman/mod.rs

Line 275 in b8e5b2c

info!("Jumped offset by {}ms", change * 1e3);

- but not these ones.

[davidv1992]

Perhaps the better solution here is to make those jumps a warning. Thinking about this, that makes a certain amount of sense to me as it is something that may cause issues (not all software likes the system time jumping around) although it can be unavoidable. What do you think @rnijveld