[time-nuts] sync computer clock ticks

Christian Vogel vogelchr at vogel.cx
Fri Jan 4 18:48:49 UTC 2008


Hi Michael,

> I've used NTP for years, but i was under the impression that it is not
> able to synchonize the clocks below 1 or 2 seconds.   Can you point me
> towards a specific article that speaks about the configuration
> parameters to get ntp sync'd that low?

at work, I use it to sync all servers and workstations to 4 stratum 1 
NTP-servers. I get ~100us offset usually. Without special hardware I'd 
say that 1usec is not possible.

Server, Gig-Ethernet, 4 hops (>=Gigabit) to ntp:
*ntp2-rz.rrze.un .GPS. 1 u  758 1024 377 1.225 **-0.179** 0.068
(HP DL380-G3, Dual 3.2 GHz P4, no powersaving)
-> Temperature fluctuates +/- 3 Deg-Celsius every 20sec due to HVAC

Client, 100Mbit, 5 hops (last 4 are better than Gigabit):
*ntp2-rz.rrze.un .GPS. 1 u  987 1024 377 1.577 **-0.111** 0.091
(P4-Celeron, 2.4 GHz, currently throttled to 300 MHz)
-> Temperature currently stable and possibly very cool, have not
  been in my office for a week :-)

My main problem is probably that ntp switches between three equally good 
servers quite frequently (it just did).

      Chris




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