[ntp:questions] dcf77 receiver makes ntp unstable? (drift and offset get jumpy)

Folkert van Heusden folkert at vanheusden.com
Tue Feb 8 13:50:21 UTC 2005


> 	However, with your local refclock being considered insane, the 
> only thing I can think of is that you might still be losing 
> interrupts as your system tries to service the serial port, and this 
> could result in your drift and offset wandering around like that.

I realised that maybe some kernel patch I included a while ago might
trigger this problem: the genetic anticipatory i/o scheduler.
So now I'm recompiling the kernel. Not without that patch but this
time with preemtive scheduling enabled, as a stop-gap more or less. If
that doesn't help, I'll try disabling the gen.ant.i/o sched.

> 	Or maybe you're clock-hopping?  Going back and forth between 
> being considered insane and the syspeer for this local refclock and 
> other upstream Stratum 1 servers, could also explain what's happening 
> to your drift and offset.

Nah, I've been looking at it since 10:00 this morning and it seems to
stick to my dcf77 receiver.


Folkert van Heusden

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