[ntp:questions] Re: where should we update sys_rootdispersion?

Dongling Duan duan at cisco.com
Tue Sep 9 04:18:06 UTC 2003


Thanks David for all your help! 

I think the box just need time to settle down. I saw sys_rootdispersion
decrease along the time:

sys_rootdispersion=15630.7
sys_rootdispersion=13536.6
sys_rootdispersion=11723
sys_rootdispersion=10152
sys_rootdispersion=8792.28
sys_rootdispersion=7614.34
sys_rootdispersion=6594.21
sys_rootdispersion=5710.76
sys_rootdispersion=4945.66
...

-dongling

"David L. Mills" wrote:
> 
> Dongling,
> 
> Indeed if you batter ntpd long and hard enough you can cause the
> frequency to clamp at the extreme and it may take quite a while to
> settle down, especially if symmetric modes are involved. The system is
> actually a network of chaotic oscillators with nonlinear feedback loops
> coupled by a nonuniform sampled data stream. Professional driver needed;
> don't try this at home.
> 
> Patience. Give it a couple hours.
> 
> Dave
> 
> Dongling Duan wrote:
> >
> > Thanks David for your explanation!
> >
> > I have a script which has more than ten testcases using the topology I
> > describe in previous email. I test all kinds of configuration and
> > combination, server, peer, broadcast, with/without authentication etc.
> > For each test, I reset clock to a random time on all box to see whether
> > we are synced or not after some time. Some times offset could be very
> > very big. Once it is synched, we check whether each peer is reached via
> > peer->reach.
> >
> > Could somehow ntpd internal state fall into some state (sys_jitter is
> > very big) because of all the configure/unconfigure, reset clock etc? So
> > the ntpd just need more time to be sane?
> >
> > -dongling
> ...



More information about the questions mailing list