Date: Thu, 27 Jan 2000 16:37:38 -0500 From: Marc Giannoni <marcg@fred.net> To: Ben Smithurst <ben@scientia.demon.co.uk> Cc: freebsd-questions@freebsd.org Subject: Re: CMOS clock and NTP Message-ID: <00012716522404.55277@versa> References: <20000127173700.A4663@strontium.scientia.demon.co.uk>
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Thanks! Good information.......
.....some time later.....
Well, "machdep.i8254_freq" did not affect the Time of Day clock, however it did
affect the interval timer...."setitimer" and "sleep". I could speed these up
or slow them down, but the time of day kept speeding ahead!
What finally worked was, "machdep.tsc_freq", which I had to change from
400911342 to 99990000 !?! This is what finally slowed the clock down,
apparently a slowdown factor of 1/4!
I'm not clear on what is happening, there is a BUG somewhere....either in
hardware or in (Ghasp!) software. NTP does not really sync either....it just
cycles throught the list of (Public) servers I've configured. My guess is
"adjtime()" is not really adjusting the time of day clock!
Marc
On Thu, 27 Jan 2000, you wrote:
> Marc Giannoni wrote:
>
> > I have a Dell Dimension P100 with a fast CMOS clock.
> > This clock will gain almost an hour a day, and NTP won't
> > sync with any servers. (I have NTP working on another host)
> >
> > #sysctl kern.clockrate
> > #kern.clockrate: { hz = 100, tick = 10000, tickadj = 5, profhz = 1024, stathz
> > = 128 }
> >
> > How can I tweak the tick? sysctl says kern.clockrate is readonly!?!
>
> look at machdep.i8254_freq instead, I tweaked that on a machine of
> mine which was gaining about 1 sec/hour and it's worked fine. (I use
> ntpdate, but with errors like that it was always doing 'step' rather
> than 'adjust' -- now it can always use 'adjust' as the error is less
> than 0.5 sec.)
>
> --
> Ben Smithurst / ben@scientia.demon.co.uk / PGP: 0x99392F7D
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