Kernel PPS processing

Gary E. Miller gem at
Thu Jun 30 04:57:10 UTC 2016

Yo Hal!

On Wed, 29 Jun 2016 21:35:49 -0700
Hal Murray <hmurray at> wrote:

> gem at said:
> > Wow.  I thought something was wrong.  My local clock offset
> > (peerstats file) has always been hanging around 100ppm.  Stable to
> > ±1ppm so I figured that was normal.  
> > After reboot the local clock offset started at 9ppm and has been
> > slowyly going down, now under 2ppm.   
> Your units don't make sense.

Yeah, I'm working on getting the descriptions just right on my graphs.

Local clock frequency offset, as opposed to local clock time offset.

Sorry I did not specify which offset, but I figure the ppm shoulda
clued you in.

> Offsets would be in units of seconds.  I assume you mean some
> fraction of a second.  A guess would be microseconds.

Nope.  ntpd has both time offsets and frequency offsets of the local clock.

To be real specific, I'm looking at field 3 of the loopstats file.
'man ntp.conf' calls that: frequency offset, with units of PPM.

Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
	gem at  Tel:+1 541 382 8588
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