I have a PC directly connected to a GPS clock with PPS signal that sets the clock to an accuracy of 5 µs (!) or less (shows in NTP as a normal server).
Now I want to measure how bad the internal software clock is. Therefore I am searching for an option to actually poll a server and don't set the time but actually let it go off.
I could mark the server as noselect in the ntp.conf file, but then ntpd won't write the loopstats file.
How to let the ntpd write the loopstats file with the offset to the server, but don't acutally set the time?