Clock Problems

Juergen Beisert juergen127 at
Fri Dec 11 06:18:22 PST 2009

On Freitag, 11. Dezember 2009, Mykal Funk wrote:
> I am use to old hardware (i486DX) having problems keeping time on the
> hardware clock. But isn't the system clock a separate thing? I am losing
> about 4 min on the system clock for every 10 minutes of real time. I've
> googled around for clock drift information. What I found suggests  that
> a system under heavy load with the 2.6.x kernel on certain hardware
> might show this symptom.

Does it also happen, if your system is idle? What is your current CONFIG_HZ_* 
setting? Try the lowest rate for your system. Also you could try to disable 
CONFIG_NO_HZ (if set) in your kernel config.

> I've yet to try it, but I've read that adding 
> "clock=pit noapic nolapic" to the boot parameters should fix it.

As a i486DX does not support any APIC hardware this parameter will not help.

BTW: If your system time drifts away due to bad crystals you should run an 
ntpd for a few days. It will use adjtimex to trim your system's settings to 
get less time drift.


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