[ntp:questions] Strange NTP problem on AMD Geode LX cards.

David J Taylor david-taylor at blueyonder.not-this-part.nor-this.co.uk.invalid
Sat Oct 3 09:38:13 UTC 2009


"Rob" <nomail at example.com> wrote in message 
news:slrnhce5df.10lk.nomail at xs7.xs4all.nl...
> Richard B. Gilbert <rgilbert88 at comcast.net> wrote:
>>> * On a system not locking stopping ntp and restarting having set the 
>>> drift
>>> file to -28, results in the drift going back to -400 over a couple of
>>> hours - so not some odd start-up state that confuses the control loop.
>>
>> This suggests that your local clock is defective!  Most properly 
>> working
>> hardware will generate an absolute value that is less than 100 and many
>> will have an absolute value less than 50.
>
> I don't think so.  This often happens with ntpd, also on systems with
> a well working clock.  There is some sort of problem with ntpd startup
> as Unruh also explained.  I have seen it many times.
>
> It is worse when you start to twiddle the config and shutdown/restart
> ntpd often.  Then it can take a very long time before it becomes stable
> again.
>
> It seems that the official standpoint is to ignore or deny these 
> problems,
> but that doesn't mean they cease to exist.

I have also seen similar problems where NTP will "go wild", with the 
computed frequency error becoming further and further from the expected 
value.  Stopping and restarting NTP will sometimes fix these problems, at 
other times it may be necessary to delete the drift file and let NTP 
establish a new value from scratch.

Cheers,
David 




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