Counting Mode 6 packets - ugly Heisenberg effect

Eric S. Raymond esr at thyrsus.com
Sat Dec 17 14:10:52 UTC 2016


In previous mail I said I was going to follow up on my long
explanation to Halof how ntpq works with a report of one change
since that description.

Fortunately, I've since solved the problem I was thought I was going
to have to write about. I had to revert "Move ntp_monitor() call to
where it catches Mode 6 packets." after Gary reported an ugly
Heisenberg effect. Because ntpmon was shipping excessively frequent Mode 6
requests, that change made the packet counter for localhost scream.

This was partly because I had the query-interval expression in intpmon
wrong - it could evaluate to 0 in which case ntpmon would spam ntpd
with continuous requests.

I have since fixed this.  Mode 6 monitoring statistics are back.
-- 
		<a href="http://www.catb.org/~esr/">Eric S. Raymond</a>

"Boys who own legal firearms have much lower rates of delinquency and
drug use and are even slightly less delinquent than nonowners of guns."
	-- U.S. Department of Justice, National Institute of
	   Justice, Office of Juvenile Justice and Delinquency Prevention,
	   NCJ-143454, "Urban Delinquency and Substance Abuse," August 1995.


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