[ntp:questions] LOCL clock reachability not 377?

Martin Burnicki martin.burnicki at meinberg.de
Mon Aug 25 16:23:05 UTC 2014


Harlan Stenn wrote:
> Rob writes:
>> Harlan wrote:
>>> All the time variables are fixed-point decimals in seconds - you
>>> should be able to say 0.001 to mean a millisecond (or -0.001 if you
>>> need to go the other direction).
>>
>> Should.   But:
>>
>>          if (pp->sloppyclockflag & CLK_FLAG1)
>>                  up->max_delta = 0;
>>          else if (pp->fudgetime2 < 1. || pp->fudgetime2 > 86400.)
>>                  up->max_delta = 4*3600;
>>          else
>>                  up->max_delta = (time_t)floor(pp->fudgetime2 + 0.5);
>
> This is a question for Juergen...
>
> H
>

Please note the 4 hours limitation has already been discussed back in 
2005, with no valuable result:
"clocktime() needs work"
https://bugs.ntp.org/417

In 2013 I opened another bugzilla issue to get SHM improved and some of 
its limitations removed:
Request for a more versatile shared memory (SHM) refclock driver
http://bugs.ntp.org/show_bug.cgi?id=2470

Now Juergen Perlinger has worked on Bug 2622 which also was due to this 
ugly 4 hours limitation:
"Synchronisation problem using SHM when time difference is more than 
four hours"
https://bugs.ntp.org/show_bug.cgi?id=2622

I haven't looked ath Juergen's changes, but I hope and trust he has 
improved the SHM driver, which is IMO a good and versatile interface to 
ntpd.


Martin
-- 
Martin Burnicki

Meinberg Funkuhren
Bad Pyrmont
Germany



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