Kernel PPS processing

Gary E. Miller gem at
Thu Jun 30 04:28:12 UTC 2016

Yo Hal!

On Wed, 29 Jun 2016 15:28:29 -0700
Hal Murray <hmurray at> wrote:

> gem at said:
> >> I'm not sure why you would expect performance to be identical.  
> > Because thhey use the same kernel generated time stamp and PLL
> > algorithm.   
> There are two chunks of PPS code in the kernel with separate RFCs.
> One is getting the time stamp.  The other is doing the PLL.  The
> in-kernel PLL is totally different from anything in ntpd.

Interesting.  So they start with the same time stamp, but PLL
differently.  I wonder why the PLL's is so different?

I'll bet the kernell converence is much faster than the ntpsec
convergence.  The best answer is likely in between.

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