[ntp:questions] Re: ntpd PLL and clock overshoot

Uwe Klein uwe_klein_habertwedt at t-online.de
Sun Oct 15 07:57:26 UTC 2006


Hal Murray wrote:
> [100% overshoot]
> 
> 
>>I believe that Dave Mills has already explained that the problem is due 
>> to changes in the adjtime() routine in both Sun Solaris and Unix. 
>>This being the case, the choices would seem to be:
>>a. Live with it.
>>b. Get Sun and the Linux developers to back out the change to adjtime() 
>>that broke ntpd.
>>c. Provide a custom adjtime() for each platform affected.  I suspect 
>>that the routine in question runs in kernel mode and may be part of the 
>>kernel so that this may be easier said than done!
> 
> 
> I assume the fix is something simple like replacing a select with
> a simple assignment.
> 
> For Linux, it would help some of us if somebody would track down
> the place that needs fixing and publish a diff.  I took a quick
> scan and didn't find it, but my kernel may be before somebody added
> that tweak.
> 
any specifics where to look?

the public visible adjtime(x) seems to live in glibc.

uwe




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