Re: [gpsd-users] Uncertain system time

[Gary E. Miller]

Yo Massimiliano!

On Wed, 2 Oct 2019 19:14:36 +0200
Massimiliano Fago <address@hidden> wrote:

> > That is a bit old.  Can you try 3.19.1~dev?  I suspect you hit the
> > bug. 
> 
> I have checkout the new 3.19.1 version. I think that now is ok.

I'm not sure why that bug happened, it went away when gpsd converted
from floating point (double) time to timespec time.

> One more question, I have all log active in ntp.conf file.

Good.  Although some prefer not to log as it adds uncertainy and
latency to the system.

> How I can generate the png file graph?

Easy.

> I looking for the ntpviz command

It is in the source package:

    ntpsec/ntpclients/ntpviz.py

It gets installed here:

    /usr/local/bin/ntpviz

> but I don't understand how it works.

You don't need to, it just works, so just use it.  :-)

> Can you make one example? Is possible to generate a graph with less
> than one day data?

I have all my servers generate daily graphs every hour, and weekly graphs
every day.  Here are my cron entries, just that simple:

3  * * * * cd /var/www/localhost/htdocs ; ntpviz @day/optionfile
13 8 * * * cd /var/www/localhost/htdocs ; ntpviz @week/optionfile


Note two things:

    1) it is built in the directory that html is served from.
    2) all the options are in optionfiles.

Here are the two options files:

     # cat /var/www/localhost/htdocs/day/optionfile
    --clip
    --name=Kong
    --nice
    --outdir=day
    --period=1
    --terminal=pngcairo

     # cat /var/www/localhost/htdocs/week/optionfile
    --name=Kong
    --nice
    --outdir=week
    --period=7
    --terminal=pngcairo

Options are documented in "man ntpviz".

Notice the option "--period=1".  That means one day.  The number is
floating point, so "--period=0.25" is 3 hours.

RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
        address@hidden  Tel:+1 541 382 8588

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    "If you can't measure it, you can't improve it." - Lord Kelvin

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