Re: RTC can't keep up the time

[Andrew Doran <ad%netbsd.org@localhost>]

On Wed, Dec 17, 2008 at 02:12:19PM -0500, Arnaud Lacombe wrote:

> I noticed a weird bug on -current (5.99.5). The hardware is new, about
> 3 month old. I didn't noticed such behavour on the previous 5.99.1:
> 
> $ sudo ntpdate 0.pool.ntp.org; sleep 20; sudo ntpdate 0.pool.ntp.org
> 17 Dec 14:02:10 ntpdate[7729]: step time server 129.128.5.211 offset
> 13.333831 sec
> 17 Dec 14:02:33 ntpdate[8640]: step time server 129.128.5.211 offset
> 3.751196 sec
> 
> $ date; sleep 20; date
> Wed Dec 17 14:02:33 EST 2008
> Wed Dec 17 14:02:49 EST 2008
> 
> it seems that each 20 seconds, I lose 3.75 seconds.
> 
> I tested with an external timer, and the delay between the two date(1)
> *is* 20 seconds.
> 
> Any hints ?

Either the selected clock is drifting or it's not being calibrated
correctly due to a bug.

Is your system using ACPI? Please post:

sysctl kern.timecounter
cpuctl identify 0

Thanks,
Andrew