On Mon, Nov 01, 2010 at 02:49:57PM +0000, David L. Mills wrote: > There is a very good reason. First, the kernel can an only be > switched between PLL and FLL mode discreetly, while the daemon has a > gradual transition between modes so that the poll interval can vary > seamlessly between 8 s and 36 hr. Second, the kernel PLL is most > useful to minimize sawtooth errors, and is no better than the daemon > loop to track incidental frequency noise. Seldom if ever is it > useful to switch to FLL mode at poll intervals less than 1024 s, > unless the incidental phase noise is less than a microsecond.
I know the kernel FLL is slightly different from the daemon FLL, but from the clknetsim tests it looked like FLL at 64s polling interval could be useful even with 100us phase noise. In any case, would it make sense to use the shorter kernel FLL when tinker allan is set to 8 or less? Similarly to the daemon loop, but only with one step. -- Miroslav Lichvar _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
