sys_fuzzMime-Version: 1.0

[Hal Murray]

esr at thyrsus.com said:
> *blink*   I think I just achieved enlightenment.  Gary, Hal, please review
> the following carefully to ensure that I haven't updated my beliefs wrongly.

If there is any discussion, it's just nit-picking.  Some of it might be 
interesting, but you have the big picture correct.


> Therefore I *deduce* that the PLL correction (the one NTP does, not the
> in-kernel one Hal tells us is associated with PPS) requires a monotonically
> increasing clock.  It's the simplest explanation for the way libntp/
> systime.c works, and it explains *everything* that has puzzled me about that
> code. 

I don't believe there is any fundamental reason why a PLL requires monotonic 
clocks.  I don't think the concept even makes sense to a PLL.  What would be 
the equivalent in a hardware PLL?  What if you were controlling temperature?

I'd guess that the monotonic/Lamport check was added in a place where it 
seemed to make sense and the clock fuzzing happened to trigger it.




-- 
These are my opinions.  I hate spam.