[ntp:questions] Further Observations (Windows NTP Jitter)

Jerry Baker jerry at novalid.invalid
Fri Oct 1 15:07:55 UTC 2004


I am starting to see a pattern with the MRTG graphs. For two days now, 
you see a spike that occurs between 6:00AM and 7:00AM. There is nothing 
that happens on the PC at that time. I am at work and so not logged in. 
However, at 6:00AM exactly there is a scripted build of the LAME MP3 
encoder in Visual Studio. This script only runs on Monday, Wednesday, 
and Friday. You will see that the spike also occured on Thursday, so 
that rules that out. I cannot imagine anything else that would cause 
that. The PC is sitting at home alone, there is no air conditioning or 
heating to kick on or off to effectuate a rapid temperature change.

You will also notice that NTP has a larger pattern to it. The graphs 
indicate a trough in the offsets at approximately 11:00PM. The offsets 
then slowly climb to a peak at around 7:00AM where they resume their 
descent. Since this variation appears to coincide with the natural 
temperature fluctuations of the room (with a slight offset), I will try 
controlling the temperature better and see if that doesn't effect a change.



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