It doesn't have anything to do with ntpd and shouldn't be used to troubleshoot it. After you use ntpdate to set the clock, use 'hwclock --systohc' to sync "running" time to your hardware clock.
The reason that ntpq was suggested with the -p options to show peering. It is supposed to sync on a reboot but if your machine crashes (or otherwise had a problem doing a proper shutdown) it could not sync it.
As NTPD is run as root, it does have access to the drift file, regardless of the ownership on the drift file.
A fluctuation of just 0.001% (0.00001, or 10 PPM) means losing or gaining about 1 second per day.
The description says to uncomment this line to log statistics.
NTP has finer grained control than that, so we look at errors of margin using 0.0001% (0.000001, or 1 PPM).
Thus: According to the web site https://groups.google.com/forum/m/? topic/comp.ntp/co Dks98gw0U the value is a calculationn made per poll and needs to be divided by 4096 to get the actual drift value in milliseconds Thanks so much for the link.
I have a machine that experienced some troubles with some of the real time stuff that I'm running.
One lead that I have is that NTP daemon may have moved the time, causing false timeouts.