Should the HAVE_KERNEL_PLL conditional be abolished?
Eric S. Raymond
esr at thyrsus.com
Mon Dec 4 16:09:17 UTC 2017
Hal Murray <hmurray at megapathdsl.net>:
> >> 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="http://www.catb.org/~esr/">Eric S. Raymond</a>
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