[ntp:questions] simple nt.conf cases for ntp-client

David Woolley david at ex.djwhome.demon.invalid
Fri Jan 24 19:06:33 UTC 2014

On 24/01/14 17:42, William Unruh wrote:
> Does it use the time from that one, or some sort of "average"? Since the
> queries of the different servers occur at different times (separated by
> about and hour, given the initial filter  at poll 10) how does it take the averagei
> if it uses the average?

If there is a prefer peer and it survives, it uses that one, otherwise 
as per clock_combine in ntp_proto.c, i.e. weighted by synchronisation 
distance (which grows with time).

8,000 seconds is more like two hours.  If that poll interval is being 
used, it is assumed that time errors don't vary much over  period 
several times that.

The weighting may change between versions.  This is 4.2.7p333.

         y = z = 0;
         for (i = 0; i < npeers; i++) {
                 x = 1. / peers[i].synch;
                 y += x;
                 z += x * peers[i].peer->offset;
         sys_offset = z / y;

Jitter code removed.

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