Re: [chrony-users] Discover when a time sync has been performed

[Bill Unruh <unruh@xxxxxxxxxxxxxx>]

What makestep? The offset is always within a millisecond of the right time.
There is no need for any step anywhere in the file. 
Not sure what you are expecting?


On Thu, 4 Jul 2013, Ignacio Verona R� wrote:

> Hi Miroslav,
>
> thanks for your answer. It partially solves my question, but I'm not able
> to see the entry in the tracking log when makestep is applied. Last lines
> of the file look like this:
>
> 2013-07-04 12:59:20 193.145.56.7     3     36.888     27.043 -1.121e-09
> > 2013-07-04 12:59:22 193.145.56.7     3     36.888     27.042 -1.999e-10
> >
> > 2013-07-04 12:59:25 193.145.56.7     3     36.888     27.041 -8.009e-11
> >
> > 2013-07-04 12:59:28 193.145.56.7     3     36.888     27.041 -1.750e-11
> >
> > 2013-07-04 12:59:30 193.145.56.7     3     36.888     27.041 -3.122e-12
> >
> > 2013-07-04 12:59:33 193.145.56.7     3     36.888     27.041 -1.252e-12
> >
> > 2013-07-04 12:59:36 193.145.56.7     3     36.888     27.041 -2.735e-13
> >
> > 2013-07-04 12:59:38 193.145.56.7     3     36.888     27.041 -4.878e-14
> >
> > 2013-07-04 12:59:41 193.145.56.7     3     36.888     27.041 -1.955e-14
> >
> > 2013-07-04 13:02:29 193.145.56.7     3     36.888     27.041 -2.559e-13
> >
> > =======================================================================
> >
> >    Date (UTC) Time     IP Address   St   Freq ppm   Skew ppm     Offset
> >
> > =======================================================================
> >
> > 2013-07-04 13:02:29 193.145.56.7     3     35.372     25.842 -9.218e-03
> >
> > 2013-07-04 13:02:35 193.145.56.7     3     35.053     24.987 -2.218e-06
> >
> > 2013-07-04 13:02:37 193.145.56.7     3     34.981     24.662 -1.912e-07
> >
> > 2013-07-04 13:02:37 193.145.56.7     3     51.432     44.243  1.820e-02
> >
> > 2013-07-04 13:02:41 193.145.56.7     3     62.654     44.994  1.025e-02
> >
> > 2013-07-04 13:02:45 193.145.56.7     3     61.990     45.978 -1.239e-02
> >
> > 2013-07-04 13:02:49 193.145.56.7     3     62.469     43.023  2.828e-03
> >
> > 2013-07-04 13:05:05 193.145.56.7     3     77.812     57.165  7.208e-02
> >
> > 2013-07-04 13:05:13 193.145.56.7     3     82.492     50.649 -2.832e-03
> >
> > 2013-07-04 13:05:17 193.145.56.7     3     82.620     46.004 -2.830e-03
> >
> > 2013-07-04 13:05:21 193.145.56.7     3     82.127     43.920 -2.164e-03
> >
> > 2013-07-04 13:05:25 193.145.56.7     3     81.555     42.269 -1.921e-03
> Should I expect some "Makestep OK" message? or it's a different state?
>
> Thanks for your help.
>
>
> 2013/7/4 Miroslav Lichvar <mlichvar@xxxxxxxxxx>
>
> > On Thu, Jul 04, 2013 at 12:32:10PM +0200, Ignacio Verona R� wrote:
> > > My question is about checking when a time sync has been performed. I'm
> > > developing an application where time sync is important. It's running on a
> > > Raspberry Pi, so time is not very good kept. When the net connection is
> > > started I notify chrony about the sources being online, and the config is
> > > set to execute a "makestep" if more than 10secs deviation is found.
> > >
> > > But, how may I check if the sycn (makestep) is already done? I've been
> > > searching the logs (syslog, tracking, measurements) but don't know what
> > may
> > > trigger my "Sync ok!" event.
> >
> > If the measured offset is larger than the makestep limit, chronyd will
> > correct the error immediately. When that happens, a message is written
> > to the system log and there should be an entry in the tracking log
> > too if it's enabled.
> >
> > If the offset is below the makestep limit, it will be corrected slowly
> > by slewing. You can monitor the remaining correction in the "System
> > time" field in the tracking report.
> >
> > > Maybe looking at the offset value and setting some threshold, so if it's
> > > lower it's ok for the app to continue?
> >
> > It depends on what exactly you want to check. You can use the chronyc
> > waitsync command, it waits for the remaining correction (and
> > optionally also for the skew) to be smaller than a specified limit.
> >
> > If you need also to be sure that an update was actually performed
> > after the sources were set online, you will need to check the time
> > stamps in tracking log or check if the Ref time field in the tracking
> > report has changed.
> >
> > Does this answer your question?
> >
> > --
> > Miroslav Lichvar
> >
> > --
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