[ntp:questions] Re: Client Clock Updates

David Woolley david at djwhome.demon.co.uk
Thu Nov 17 23:04:36 UTC 2005


In article <1132258343.789720.234890 at o13g2000cwo.googlegroups.com>,
Steve Pope <spope at hbk.com> wrote:

> How do you control how often a client updates it local clock from the
> ntp server?

ntpd doesn't update its local clock when it accesses the servers.
The interval at which it updates the local clock is fixed (if I remember
correctly, it is the clock interrupt interval for the kernel PLL and
otherwise every 4 seconds).

The interval at which it samples the offset between the local servers 
and the local clock (but does not change the local clock to remove that
offset) is selected adaptively to get the best overall stability whilst
responding reasonably quickly to major environmental changes.

This is one of those questions where the answer is, if you need to
ask the question, you should not be trying to influence this aspect of
the software.




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