On 2/14/2012 01:49, David Lord wrote:
A C wrote:
On 2/13/2012 15:44, David Lord wrote:

Recent ntpd is supposed to handle that level of frequency
offset but most of my pcs have had the frequency offset
adjusted to be < 10 ppm which is done when I build a kernel
with "options PPS_SYNC" and "options TIMER_FREQ=119????".

This kernel does have PPS_SYNC enabled but I'm not using it right now
since I'm still debugging ntpd/libc. I'll start using it next week
after I know ntpd will survive a week straight.

How do you determine the timer frequency number? Trial and error?

At one time I could find it in the documentation but
not when I last did a search.

AFAIK it was supposed to be self calibrating so the
ability for adjustment might be dropped. Unfortunately
the self calibration can be > 50ppm out.


PC me6000 is using kernel compiled for a different pc:
me6000 $ dmesg | grep timecounter
....
timecounter: Timecounter "i8254" frequency 1193182 Hz quality 100
....

I have timecounter in my dmesg also but it doesn't show up anywhere in the kernel configuration for compiling:

# dmesg | grep time
timecounter: Timecounters tick every 10.000 msec
timer0 at mainbus0 ioaddr 0xf3000000 ipl 10: delay constant 18, frequency = 1000000 Hz
timecounter: Timecounter "timer-counter" frequency 1000000 Hz quality 100
timecounter: Timecounter "clockinterrupt" frequency 100 Hz quality 0

I'll have to ask the NetBSD people where the value is hiding.
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