git: dntpd - Improve offset correction precision

Matthew Dillon dillon at crater.dragonflybsd.org
Sat Mar 15 09:34:56 PDT 2014


commit 4c77cdeb9acda04d7fd188dd86c72a08204482ed
Author: Matthew Dillon <dillon at apollo.backplane.com>
Date:   Sat Mar 15 09:28:55 2014 -0700

    dntpd - Improve offset correction precision
    
    * Offset corrections are more accurate with more samples (whereas frequency
      corrections are more accurate when the first and last sample are far apart
      in the time domain).
    
    * Even though dntpd uses a standard deviation test to conditionalize offset
      corrections, it is still possible to get false positives with only 4
      samples.
    
    * Once dntpd has gone into maintainance mode increase the number of
      required samples for an offset correction from 4 to 8.  This makes
      the standard deviation more accurate, reduces false positives, and
      improves stability.
    
    * Retain the original mechanic during aquisition so dntpd applies corrections
      sooner rather than later when first started.

Summary of changes:
 usr.sbin/dntpd/client.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/4c77cdeb9acda04d7fd188dd86c72a08204482ed


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