| Re: [chrony-dev] [PATCH] MacOS X - add drift removal |
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On Thu, Jul 30, 2015 at 09:50:26AM +1200, Bryan Christianson wrote:
> The darwin kernel implementation of adjtime() does not require the adjustment to
> be aligned to a tickadj boundary, and we can apply adjustments to the nearest microsecond.
> Rounding is accounted for by adding any rounding errors back into the offset.
Applied, thanks. What offset do you now see? I guess it doesn't solve
the problem you were trying to fix in your previous patch.
I was wondering if the error of the clock could be minimized by
including in the requested adjustment a prediction of the offset in
the middle of the update interval so the mean value is close to zero
if the drift doesn't change much. E.g. with a drift of 10 ppm and
current offset of 20 microseconds, request 25 microsecond adjustment
instead of 20, so the clock overshoots a bit and reaches zero offset
in about 0.5 seconds.
--
Miroslav Lichvar
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