The clock is running too fast

[Stephen Liu]

Hi Dan,

The system clock has been running correctly more than 16 hours.

> I'm sorry, I don't know what 'ntc' is.  Do you mean 'ntp'?  You can use ntp
> or not ... if your timing hardware is off, ntp will constantly try to slew
> the time back to where it should be, which will a) mean your systems
> concept of time is very non-linear and b) fill the log with warning
> messages.  It's actually a good check to see if the timer's good (although
> an slmost equally good check is to sit there and look at the clock).

Oh sorry for my typing mistake.  Yes I meant 'ntp'.  It synchronyses the 
system clock.  Even if the PC is not running round the clock.  Whenvever you 
turn on the PC, it checkes the time and corrects it.  I have it setup on a 
Debian PC.;

> I forgot to mention that besides changing /etc/sysctl.conf, you have to
> reboot.  If you don't want to reboot, you will have to do "sysctl
> kern.timecounter.hardware=i8254" at a prompt.  But I'm not sure if that's a
> value that can be set after the system boots.

I have to reboot the PC otherwise the system clock will not be adjusted, still 
running on double speed.

> I suggested "i8254" because it's the only device that was supplying good
> time values on my system.  If you have trouble with that device, you might
> also want to try "TSC".

$ dmesg.Thetimeclock
dmesg.Thetimeclock: not found
$ dmesg | grep Timecounter
Timecounter "i8254" frequency 1193182 Hz quality 0
Timecounter "ACPI-safe" frequency 3579545 Hz quality 1000
Timecounter "TSC" frequency 350796390 Hz quality 800
Timecounters tick every 10.000 msec

What are their difference in function between i8254/ACPI-safe/TSC

B.R.
Stephen


> -----Original Message-----
> From: owner-freebsd-questions at freebsd.org
> [mailto:owner-freebsd-questions at freebsd.org]On Behalf Of Stephen Liu
> Sent: March 19, 2004 01:12
> To: questions at freebsd.org
> Subject: Re: The clock is running too fast
>
>
> Hi Dan,
>
> Thanks for your advice.
>
> > I had a similar problem on one of the machines at work.  Here is a memo I
> > made to myself to remind me of how to fix the problem in the future:
> >
> > The "ACPI-safe" Timecounter does not work (it is way, WAY too fast).  To
> > get around this, add the following line to /etc/sysctl.conf:
> >
> > kern.timecounter.hardware=i8254
>
> Added above line to /etc/sysctl.conf
>
> $ cat /etc/sysctl.conf
> vfs.usermount=1
> kern.timecounter.hardware=i8254
>
> Now only 2 lines in this file.
>
> I have adjusted the clock thereafter and will check it again later
>
> > There are multiple pieces of hardware capable of supplying timing
> > information to the OS.  "dmesg | grep Timecounter" should give you a list
> > of all such devices.
> >
> > I think this is an ACPI-related problem, since that is the technology I
> > understand the least at the moment.
>
> $ dmesg | grep Timecounter
> Timecounter "i8254" frequency 1193182 Hz quality 0
> Timecounter "ACPI-safe" frequency 3579545 Hz quality 1000
> Timecounter "TSC" frequency 350797051 Hz quality 800
> Timecounters tick every 10.000 msec
>
> Shall I run 'ntc' to synchronize the clock.
>
> B.R.
> Stephen
>
> > -----Original Message-----
> > From: owner-freebsd-questions at freebsd.org
> > [mailto:owner-freebsd-questions at freebsd.org]On Behalf Of Stephen Liu
> > Sent: March 18, 2004 21:47
> > To: questions at freebsd.org
> > Subject: The clock is running too fast
> >
> >
> > Hi folks,
> >
> > AMD CUP
> > FreeBSD 5.2
> >
> > The clock on KDE desktop is running on double speed compelling me to
>
> adjust
>
> > it
> > periodically.  Kindly advise how to fix this problem.
> >
> > TIA
> >
> > B.R.
> > Stephen Liu