Bug#773252: systemd-timesyncd syncs time about once per minute

[Jos van Wolput]

On 12/16/2014 09:31 PM, Michael Biebl wrote:
> Am 16.12.2014 um 14:07 schrieb Michael Biebl:
>> Am 16.12.2014 um 04:45 schrieb Jos van Wolput:
>>> Package: systemd
>>> Version:  215-8 and 218-1
>>> Severity: normal
>>>
>>> Dear Maintainer,
>>>
>>> Systemd-timesyncd syncs time about once per 60 seconds.
>>
>> What makes you think systemd-timesync syncs the clock once every 60 seconds?
>
> I just studied the code and timesyncd starts with a minimal 32 second
> interval (NTP_POLL_INTERVAL_MIN_SEC) which is increased until it reaches
> the maximum 2048 second polling interval (NTP_POLL_INTERVAL_MAX_SEC). It
> seems to use an exponential like back-off algorithm as shown by the journal
>
>> Dez 16 14:07:41 pluto systemd-timesyncd[12409]: interval/delta/delay/jitter/drift 32s/+0.253s/0.028s/0.000s/+500ppm
>> Dez 16 14:08:13 pluto systemd-timesyncd[12409]: interval/delta/delay/jitter/drift 64s/-0.005s/0.025s/0.002s/+460ppm
>> Dez 16 14:09:17 pluto systemd-timesyncd[12409]: interval/delta/delay/jitter/drift 128s/-0.022s/0.040s/0.008s/+373ppm
>> Dez 16 14:11:25 pluto systemd-timesyncd[12409]: interval/delta/delay/jitter/drift 128s/-0.053s/0.024s/0.050s/+165ppm
>> Dez 16 14:13:33 pluto systemd-timesyncd[12409]: interval/delta/delay/jitter/drift 256s/+0.030s/0.124s/0.055s/+165ppm (ignored)
>> Dez 16 14:17:50 pluto systemd-timesyncd[12409]: interval/delta/delay/jitter/drift 256s/-0.056s/0.026s/0.052s/+55ppm
>> Dez 16 14:22:06 pluto systemd-timesyncd[12409]: interval/delta/delay/jitter/drift 512s/-0.012s/0.025s/0.050s/+43ppm
>> Dez 16 14:30:38 pluto systemd-timesyncd[12409]: interval/delta/delay/jitter/drift 1024s/+0.046s/0.149s/0.059s/+43ppm (ignored)
>
> roughly 30s -> 1m, 1m -> 2m, 2m -> 4m, 4m -> 8m ...
>
> This looks like a sensible approach to me.
>

After half an hour I stll get an interval of 32. it doesn't increase exponentialy:

Dec 16 21:24:42 debian systemd-timesyncd[24099]: interval/delta/delay/jitter/drift 64s/+0.030s/0.192s/0.043s/+500ppm
Dec 16 21:25:47 debian systemd-timesyncd[24099]: interval/delta/delay/jitter/drift 32s/+0.194s/0.095s/0.154s/+500ppm
Dec 16 21:26:19 debian systemd-timesyncd[24099]: interval/delta/delay/jitter/drift 32s/+0.084s/0.111s/0.142s/+500ppm
.....
Dec 16 22:01:01 debian systemd-timesyncd[24099]: interval/delta/delay/jitter/drift 32s/+0.065s/0.116s/0.018s/+500ppm
Dec 16 22:01:33 debian systemd-timesyncd[24099]: interval/delta/delay/jitter/drift 32s/+0.065s/0.110s/0.017s/+500ppm
Dec 16 22:02:05 debian systemd-timesyncd[24099]: interval/delta/delay/jitter/drift 32s/+0.062s/0.104s/0.015s/+500ppm
Dec 16 22:02:38 debian systemd-timesyncd[24099]: interval/delta/delay/jitter/drift 32s/+0.062s/0.097s/0.005s/+500ppm
Dec 16 22:03:10 debian systemd-timesyncd[24099]: interval/delta/delay/jitter/drift 32s/+0.110s/0.097s/0.019s/+500ppm