A C wrote:
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.
Most likely my config is i386 specific but it's possible
there are other methods to adjust the frequency. From your
dmesg it looks to be your clock is at 1 MHz.
I searched through my NetBSD-5 docs and can't find mention
of TIMER_FREQ. The means of adjustment by that options line
does still work on i386 though. I've grepped /usr/src/sys/arch
for that text and it does appear in other arch besides i386
but not sparc or sparc64.
David
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