Re: [chrony-users] Fwd: Chrony malfunctioning at beaglebones

[Nuno Gonçalves <nunojpg@xxxxxxxxx>]

On Mon, Aug 17, 2015 at 11:20 AM, Miroslav Lichvar <mlichvar@xxxxxxxxxx> wrote:
> It looks like the output was captured soon after chronyd was started.
> With only 4 measurements spread over 9 seconds such large frequency
> error wouldn't be unusual. What do you see when chronyd is running for
> an hour?
>
> To further debug this it might be useful to configure chronyd to not
> touch the clock by adding the noselect option to all servers specified
> in the config file and enable the measurements and statistics logs
> (see the logdir and log directives).
>
> It could be a bug in the clock source that is used on the BB. You
> could try a different clock source if there is more than one
> available.

I checked and I have a single clock source:

debian@bbw1:~$ cat
/sys/devices/system/clocksource/clocksource0/available_clocksource
timer1

Note that I tried to start chrony in a clean state, without a chrony.drift file:

debian@bbw1:~$ sudo systemctl stop chrony
debian@bbw1:~$ sudo rm /var/lib/chrony/*
debian@bbw1:~$ sudo reboot

After over 30 minutes the machine that have is not adjusting the clock
(servers with noselect), don't have any unreasonable estimate, but the
one adjusting the clock still have very large errors:

debian@bbw1:~$ uptime
 00:39:28 up 37 min,  1 user,  load average: 0.11, 0.04, 0.03
debian@bbw1:~$ chronyc sourcestats
210 Number of sources = 3
Name/IP Address            NP  NR  Span  Frequency  Freq Skew  Offset  Std Dev
==============================================================================
ns.rnl.tecnico.ulisboa.pt   4   3   715 -71491.055  17976.291   -16.6s   199ms
adsl-62-48-148-210.ptprim   4   3   715 -71394.406  14362.602   -16.4s   230ms
a88-157-128-22.cpe.netcab   4   3   956 -72689.414  28005.160   -17.2s   382ms
debian@bbw1:~$ chronyc sources
210 Number of sources = 3
MS Name/IP address         Stratum Poll Reach LastRx Last sample
===============================================================================
^* ns.rnl.tecnico.ulisboa.pt     3   8   377   233   +220ms[ -16.6s] +/-   11ms
^- adsl-62-48-148-210.ptprim     3   8   377   233   +218ms[ +218ms] +/-   83ms
^- a88-157-128-22.cpe.netcab     3   8   375   227   -169ms[ -169ms] +/-   69ms
debian@bbw1:~$ chronyc tracking
Reference ID    : 193.136.164.1 (ns.rnl.tecnico.ulisboa.pt)
Stratum         : 4
Ref time (UTC)  : Mon Aug 17 19:53:42 2015
System time     : 493154176.000000000 seconds slow of NTP time
Last offset     : -16.801349640 seconds
RMS offset      : 13.358787537 seconds
Frequency       : 0.000 ppm fast
Residual freq   : -71491.055 ppm
Skew            : 1000000.000 ppm
Root delay      : 0.021884 seconds
Root dispersion : 270.499451 seconds
Update interval : 238.8 seconds
Leap status     : Normal

Note this machine have the clock so long in the past because the
default debian config does not enable steps, and the power on date is
Jan 1 2000. This doesn't make any difference.

Would you like remote access to the machine? I have a clean install of
debian, so you can hack it at will. If so please send me your public
key.


Thanks,
Nuno

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