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From: Gary E. Miller
Subject: Re:
Date: Thu, 4 Jun 2020 10:51:18 -0700

Yo артур!

On Thu, 04 Jun 2020 19:23:21 +0300
артур хайруллин <> wrote:

> i rebuild gpsd-3.20 twice, first time i switched off writing to SHM0
> and second time to SHM1 after that I record SHM0 and SHM1 data when
> gpsd was running into different logs 

Not sure why, but if it works for you.  You could just use ntpshmmon to
capture SHM(0) and SHM(1) at runtime.

    $ ntpshmmon > shm.log

> > All you need is to call ntp_write(). Call it with the SHM pointer,
> >the "real" time and "clock" time. Done. Converting that to python
> >will be interesting.  
> Next step was to write code putting above logs to SHM0 and SHM1
> respectively. After all i stopped gpsd and launched those binaries.

Easy, ntp_write()

> >  chronyd is better tuned to working with just one source. But no
> >reason NTPsec can't be improved.  
> I use ntp daemon build from ntp 4.2.6 sources.

We prefer NTPsec, but NTP Classic is usually OK.

> Now i see strange situation as for me. Ntpd reads data from SHM if my
> binary launched and update output

Looks normal to me.  What did you not like?

> but i can’t understand. My logs have  Thu, Jun  4 2020 14:00 — 14.30
> events. But ntpd eats logs and output real time 19:10. 

Good thing too.  ntpd prevented you from setting a bad system time from
bad imput.  How to break ntpd is better asked on an NTP list.  But for
starters, by default ntpd wants 3 sources to agree before changing the
system time.  Also by default nptd only makes large changes to system
time on startup.  Both good things to prevent user from shooting
themselves in the foot.

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

            Veritas liberabit vos. -- Quid est veritas?
    "If you can't measure it, you can't improve it." - Lord Kelvin

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