Date: Tue, 05 Apr 2005 15:01:07 +0300 From: Andriy Gapon <avg@icyb.net.ua> To: Bob Bishop <rb@gid.co.uk> Cc: David Magda <dmagda@ee.ryerson.ca> Subject: Re: Kernel NTP flipping between FLL and PLL modes Message-ID: <42527E03.5090805@icyb.net.ua> In-Reply-To: <6.2.0.14.2.20050401183743.04813c10@gid.co.uk> References: <1112365401.00269464.1112352602@10.7.7.3> <1112372627.00269546.1112361001@10.7.7.3> <1112372655.00269555.1112362202@10.7.7.3> <424D7911.8060805@icyb.net.ua> <6.2.0.14.2.20050401183743.04813c10@gid.co.uk>
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on 01.04.2005 20:40 Bob Bishop said the following:
>
> Unlikely I think. As I said, I've got several machines on the same LAN:
> the 5.3's misbehave; the others don't.
#define CLOCK_ALLAN 1500.
...
double allan_xpt = CLOCK_ALLAN;
...
if (ULOGTOD(sys_poll) > allan_xpt / 2) {
...
if I understand the above "random" lines of code in
contrib/ntp/ntpd/ntp_loopfilter.c correctly, then PLL<->FLL switch
occurs when polling interval goes 512<->1024, which is perfectly
possible under certain conditions with default ntp settings: minpoll=64,
maxpoll=1024 if ntp.conf(5) can be trusted.
BTW, "tinker allan" part of the man page seems to not be correct - it
has 1024 for default value when the code has 1500 as you can see.
As I understand between 5.2.1 and 5.3 ntpd version changed from 4.1.1b
to 4.2.0 and changes in this PLL/FLL area were significant, so I am not
sure what is right and what is wrong here but I am going to experiment
with tinker-ing allan to 2048 as Christian Hiris has suggested:
http://lists.freebsd.org/pipermail/freebsd-questions/2004-November/065529.html
P.S. BTW, what rules polling interval value increase/decrease ?
--
Andriy Gapon
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