[ntp:questions] problem with ntpd refclock and pps via parallel port

unruh unruh at wormhole.physics.ubc.ca
Thu Feb 4 15:33:36 UTC 2010

On 2010-02-04, David Lord <snews at lordynet.org> wrote:
> unruh wrote:
>> On 2010-02-03, David Lord <snews at lordynet.org> wrote:
>>> Hal Murray wrote:
>> Three possibilities. 
>> a) if you run linux/bsd, run chrony. It corrects for temp drifts much
>> much faster. 
> That's out at moment as chrony isn't sufficiently stable and
> backwards compatible. From my tests, I'd say offsets are lower

Which version of chrony? It has received extensive alteration in the
past few months, and chrony 1.24 is just coming out. 

> than ntpd by at least a factor of 3. Problem is monitoring
> with chronyc requiring same version on remote as chronyd on

Yes, because of all the changes the chronyc and chronyd must be the same

> server. I've also had complete lockups when attempting to peer
> chrony with ntpd.

That is much more serious. Note that I have been running 10 chrony
machines from one ntp server for the past 2 years and have never seen a
lockup. Can you give more information, at least to
chrony-dev at chrony.tuxfamily.org

On older versions of chrony, there was a problem with the rtc. Linux has
been changing its rtc code because of hpet, and the older chrony code
interacts badly with the rtc. Originally, with the original rtc, chrony
would turn on rtc interrupts. However, the rtc would return immediately
with some sort of "stored up" interrupt. this would cause the time to be
way out( the interrupt is supposed to occur on the boundary when the
seconds marker in the rtc turned over). In trying to fix this, I would
call it twice, but with the newer hpet that would freeze chrony waiting
for the read. This code has now been changed, and the freezes have
Note that the above had nothing to do with ntp as server.

> I've attempted to subscribe to mailing lists and had
> confirmation but not seen anything from the list nor seen my
> problem reports sent to the lists.

Are you using the new location? chrony had to move its hosting services
because the old host shut down as a host. (sunsite). It is now at
chrony.tuxfamily.org There has been a large number of posts from
chrony-dev in the past few months. 
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