[LinuxPPS] Sub-millisecond, kernel-config etc.

[Johan Bejeryd]

Hello!

I'm trying to get sub-millisecond precision and accuracy for time keeping
with Linuxpps and kernel 2.6.23.1.

I've followed the wiki, but so far both offset and jitter are above 1
millisecond. I guess there are some other tricks you're doing for example
with the kernel config?
I've looked at Steven Bjorks performance monitoring and the results there
are way better than mine.

So what are your kernel configs? From previous postings I've understood that
the tickless option is no good. What Hz-value are you using - does it
even matter? And what about kernel preemtion? Also do you disable apic
and acpi? Do you use any additional ntp or kernel patches than what is
described in the wiki?

Finally, for your setup, how long does it to take before the offset is
stable below 100 microseconds?  Is it a matter of hours or minutes?

Regards
/Johan
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