[ntp:questions] ntpd: time reset problem

Unruh unruh-spam at physics.ubc.ca
Wed Sep 16 01:12:09 UTC 2009


David Lord <snews at lordynet.org> writes:

>Unruh wrote:
>> David Lord <snews at lordynet.org> writes:
>.......
>>> On Ubuntu it's made more difficult than it needs be as
>>> both default to running from startup. I've been trying
>>> to get radioclocks to work so need ntpd installed for
>>> those.  Anyway I'll try getting chrony installed
>>> standalone.
>> 
>> Lichvar now has a version of chrony whith shm support through which you
>> could run your radio clock. He also has a hack for ntpd with will use
>> any of its refclocks to feed data to chrony and thus get all of the ntp
>> support into chrony. (ntp runs but does nothing but feed refclock
>> readings to chrony)

>Any chance of a link to this as I've no problem trying on
>either Ubuntu or NetBSD. I'm on chrony mailing list but it's
>very quiet.

chrony-dev list.


>>> Radioclock idea was for when no dialup or lan was
>>> available but suffers same problem for mobile use that
>>> ntpd doesn't converge fast enough to be useful when
>>> several seconds off when started. It would be handy if
>>> refclock drivers had a step option but I can't see
>>> anything like that documented.
>> 
>> Again, chrony does, and yes it does work.

>I'm sold

>Meanwhile I'll see if ntpd will step from refclock source as
>I'd not considered it possible so not bothered to try.

The refclock support in chrony  is still in the testing stage, so your milage
 may vary (ie alpha code).


http://fedorapeople.org/~mlichvar/chrony/ntp-chrony.patch
for the ntp pach
git clone http://fedorapeople.org/~mlichvar/chrony/chrony.git
for the patched chrony.
But neither is really necessary for you, as the change is to try to get
chrony to use refclock support. If you just need network, chrony already
does that. (Chrony 1.23 which is in most of the distros) The one thing
that is still wonky is the real time clock support, since Linux has
changed that in the past couple of years, breaking almost everything
that uses the RTC. ( the key thing it used to do is give an interrupt on
the clock seconds rollover. That is now completely broken. )







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