[ntp:questions] Precision changed after upgrade from ntp 4.2.4p4 to 4.2.6p2

Caecilius nospam at spamless.invalid
Sun May 4 19:29:26 UTC 2014


After upgrading ntp from 4.2.4p4 to 4.2.6p2 as part of a Linux upgrade
from Debian Lenny to Squueze, I've noticed that the precision variable
has changed from -20 to -22. So it appears that my clock has now got a
better precision. But the hardware is unchanged, and I'm running the
same kernel.

I thought the precision was dependent on the "granularity" of the
system clock, which I would have expected to be independent of the ntp
version and any other userland code.  Am I misunderstanding something
perhaps?

Here's the outputs of "ntpq -c rv" on both versions:

ntpq -c rv for ntp 4.2.4p4:

assID=0 status=06f4 leap_none, sync_ntp, 15 events,
event_peer/strat_chg,
version="ntpd 4.2.4p4 at 1.1520-o Sun Nov 22 17:34:54 UTC 2009 (1)",
processor="i686", system="Linux/2.6.32.61-nta-20405", leap=00,
stratum=3, precision=-20, rootdelay=11.891, rootdispersion=82.127,
peer=60194, refid=178.18.118.13,
reftime=d700bca2.cf74a3b2  Tue, Apr 22 2014 11:02:10.810, poll=10,
clock=d700c225.252de5e0  Tue, Apr 22 2014 11:25:41.145, state=4,
offset=-0.307, frequency=-89.946, jitter=0.434, noise=0.266,
stability=0.029, tai=0

ntpq -c rv for ntp 4.2.6p2

associd=0 status=0615 leap_none, sync_ntp, 1 event, clock_sync,
version="ntpd 4.2.6p2 at 1.2194-o Sun Oct 17 13:45:13 UTC 2010 (1)",
processor="i686", system="Linux/2.6.32.61-nta-20405", leap=00,
stratum=3,
precision=-22, rootdelay=31.619, rootdisp=60.232, refid=217.114.59.3,
reftime=d705fe90.065494fe  Sat, Apr 26 2014 10:44:48.024,
clock=d7060569.8677132b  Sat, Apr 26 2014 11:14:01.525, peer=6347,
tc=10,
mintc=3, offset=0.161, frequency=-89.952, sys_jitter=0.247,
clk_jitter=0.196, clk_wander=0.017



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