Re: soekris box still keeps terrible time
"James K. Lowden" <[email protected]>
| Newsgroups | gmane.os.netbsd.help |
|---|---|
| Message-ID | <[email protected]> |
David Lord wrote: > I use ntpd to sync to internet time. A few of my pcs have clocks too > far out for ntpd to work effectively as the natural clock drift is at > a greater rate than ntpd can lock to. The fix is to adjust the value > of TIMER_FREQ in kernel configuration to offset the system clock > drift. I aim for within -10 ppm to 0 ppm. Of course temperature and > power supply voltage can cause fairly wide variation so near is good > enough vs >>500 ppm drifts of some pcs. Other pcs are within 30 ppm > without any tweaking. > > eg. from K6X400_0.32 > ! # K6X400 is approx -60 ppm so aim for > +50ppm change > ! # default 1193182 > ! # for +68 > ! options TIMER_FREQ=1193250 Thank you, David. This is very helpful, if still a bit mysterious. Here's what I'm seeing: cherry$ grep ntpd /var/log/messages |head Nov 15 11:09:29 cherry ntpd[29870]: time reset -2.326574 s Nov 15 11:09:29 cherry ntpd[29870]: frequency error -512 PPM exceeds tolerance 500 PPM Nov 15 11:14:53 cherry ntpd[29870]: frequency error -512 PPM exceeds tolerance 500 PPM Nov 15 11:34:10 cherry ntpd[29870]: time reset -3.754409 s Nov 15 11:34:10 cherry ntpd[29870]: frequency error -512 PPM exceeds tolerance 500 PPM Nov 15 11:39:33 cherry ntpd[29870]: frequency error -512 PPM exceeds tolerance 500 PPM Nov 15 11:54:35 cherry ntpd[29870]: time reset -2.699728 s Nov 15 11:54:35 cherry ntpd[29870]: frequency error -512 PPM exceeds tolerance 500 PPM Nov 15 11:59:57 cherry ntpd[29870]: frequency error -512 PPM exceeds tolerance 500 PPM Nov 15 12:16:59 cherry ntpd[29870]: time reset -3.915989 s cherry$ config -x /netbsd | grep TIMER options TIMER_FREQ=1189200 I don't know what units TIMER_FREQ is in. Taking a naive guess, I add 512 to it, giving me 1189712. Since you suggest overcompensating, perhaps 1189800? Is that the idea? --jkl