Re: PPS in GPSD vs Chrony

[Dennis Law]

Hello Gary, Miroslav,

Thank you very much for your replies.

Our doubts were clarified.

Thank you.

On Wed, Jul 1, 2020 at 2:12 AM Gary E. Miller <gem@rellim.com> wrote:

Yo Miroslav!

On Tue, 30 Jun 2020 12:39:03 +0200
Miroslav Lichvar <mlichvar@redhat.com> wrote:

> On Tue, Jun 30, 2020 at 12:49:13AM -0700, Gary E. Miller wrote:
> > Miroslav Lichvar <mlichvar@redhat.com> wrote:
> >   
> > > For example, I set the PPS on my ublox units to
> > > 32 Hz to get more samples and improve the stability. 
> >
> > Interesting.  Do you have data on this configuration compared to
> > plain PPS? 
>
> No, I can't find any data that would compare a 32Hz PPS to 1Hz PPS
> directly. It's been a while since I experimented with it. The jitter
> of samples updating the clock should roughly improve with a square
> root of the PPS rate.


An ntpviz of different polling rates on several of my hosts showed optimal
poll depends on hardware, and is usually between 2 and 4 seconds.  Depending
on whether you are optimings for Frequency offset or Jitter.

If you repear your experiments I'd help you get some data,

RGDS
GARY
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