Kernel PPS processing

Gary E. Miller gem at
Thu Jun 30 18:47:00 UTC 2016

Yo Hal!

On Thu, 30 Jun 2016 02:15:36 -0700
Hal Murray <hmurray at> wrote:

> gem at said:
> > I took another look, and realized I misunderstood the y axis.  And
> > that you are plotting loopstats and I'm looking at offsets.  So not
> > the bad I thought.   
> I can't figure out what that means.

It means your graph is not what I thought it was, so ignore my original

> I was plotting the offset column from loopstats.

Which offset column from loopstats?  There are two offset in there.
Ah, I see below from column 2, the time offset.

> From another handy graph:
> set ylabel "Offset ms"
> set y2label "Drift PPM"

So, essentially the same as my first graph here, but different scaling:

I added the cstate boot parameter.  Made a huge difference, but I'll
need a week to get a lot of data.

Loopstats Frequency Offset, went from 100 ppm to 0.4 ppm ± 0.2 ppm!

Now I can see when the LF goes up the timing suffers.

How does yours compare to the current graph?

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