Should the HAVE_KERNEL_PLL conditional be abolished?

Eric S. Raymond esr at
Mon Dec 4 16:09:17 UTC 2017

Hal Murray <hmurray at>:
> >> First: capture pulse timing info.
> >> Second: adjust "drift" on system clock
> >> Third: in kernel PLL to adjust drift from PPS pulses
> > It *is* clear enough that ntp_adjtime() is a prerequisite for any of the
> > above three things to go on. 
> You need drift correction implemented in the kernel to get decent 
> timekeeping.  ntp_adjtime is just the API.

For the drift correction, yes.  Am I correct that it doesn't do the
other two things?

> I'd be happy to assume we have drift correction.  If not, there is no point 
> in running  ntpd.  Just run sntp occasionally.

That was my reasoning, yes.

>                                           I don't think we should 
> require ntp_adjtime as the API,
> OpenBSD has adjfreq.
>        adjfreq(const int64_t *freq, int64_t *oldfreq);
> I thought I fixed things to use it, but I can't find any references to it so 
> I don't know what's going on.

I don't think this has ever been supported, not anyhere I've seen anyway.
		<a href="">Eric S. Raymond</a>

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