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Date:      Fri, 9 Apr 1999 15:49:38 +0100 (BST)
From:      Mark Powell <M.S.Powell@ais.salford.ac.uk>
To:        Mike Smith <mike@smith.net.au>
Cc:        freebsd-stable@freebsd.org, phk@freebsd.org
Subject:   Re: Real time clock problem in 3.1-STABLE 
Message-ID:  <Pine.BSF.4.05.9904091544260.31609-100000@plato.salford.ac.uk>
In-Reply-To: <199904081930.MAA01011@dingo.cdrom.com>

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On Thu, 8 Apr 1999, Mike Smith wrote:

> > Installed 3.1-STABLE on an Apricot Shogun server. xntpd wouldn't sync time
> > correctly though. I set it up just as I do on any other machine. However,
> > on the same machine RedHat 5.2 can sync the time just fine.
> >   FreeBSD had problems both before and after the recent kernel clock mods.
> > I notice that with 3.1-S looking at the clocks at boot up, it would appear
> > that over 40 reboots, the TSC clock has varied from 126668897 to
> > 132002659, a variance of almost 5%. Is this normal? Whereas when Linux
> > boots up the variance in processor clock speed is only about 1000Hz. Could
> > this be causing the time problems, and if so is there anyway I can fiddle
> > with tickadj or something to let xntpd work on this machine?
> >   Unfortunately I'm going to have to go with Linux on this machine if
> > 3.1-S can't sync the time correctly. Anyone help? Cheers.
> 
> The problem is probably our "advanced" timecounter code being screwed 
> by the Apricot's firmware.  You might try
> 
> sysctl -w kern.timecounter.method=1
> 
> and see if that helps.  Also talk to phk@freebsd.org about this if you 
> haven't already.

Tried that and it makes no difference. This machine has a single 133MHz
Pentium. I notice on only two occasions that xntpd was able to sync time
correctly, that at boot-up the clock speed was read correctly:

Mar 12 15:44:33 mimas /kernel: FreeBSD 3.1-STABLE #0: Mon Mar  8 14:52:37
GMT 1999
Mar 12 15:44:33 mimas /kernel:
Mar 12 15:44:33 mimas /kernel: Timecounter "i8254"  frequency 1193182 Hz
Mar 12 15:44:33 mimas /kernel: Timecounter "TSC"  frequency 133335819 Hz
Mar 12 15:44:33 mimas /kernel: CPU: Pentium/P54C (133.34-MHz 586-class
CPU)
Mar 12 15:44:33 mimas /kernel: Origin = "GenuineIntel"  Id = 0x525
Stepping=5

This morning I rebooted, it again read the clock correctly and xntpd was
able to sync time.

Apr  9 12:29:16 mimas /kernel: FreeBSD 3.1-STABLE #0: Wed Mar 24 11:49:30
GMT 1999
Apr  9 12:29:16 mimas /kernel:
Apr  9 12:29:16 mimas /kernel: Timecounter "i8254"  frequency 1193182 Hz
Apr  9 12:29:16 mimas /kernel: Timecounter "TSC"  frequency 133335989 Hz
Apr  9 12:29:16 mimas /kernel: CPU: Pentium/P54C (133.34-MHz 586-class
CPU)
Apr  9 12:29:16 mimas /kernel: Origin = "GenuineIntel"  Id = 0x525
Stepping=5

However, I've rebooted again and the time is drifting again:

Apr  9 15:25:13 mimas /kernel: FreeBSD 3.1-STABLE #0: Wed Mar 24 11:49:30
GMT 1999
Apr  9 15:25:13 mimas /kernel:
Apr  9 15:25:13 mimas /kernel: Timecounter "i8254"  frequency 1193182 Hz
Apr  9 15:25:13 mimas /kernel: Timecounter "TSC"  frequency 132002173 Hz
Apr  9 15:25:13 mimas /kernel: CPU: Pentium/P54C (132.00-MHz 586-class
CPU)
Apr  9 15:25:13 mimas /kernel: Origin = "GenuineIntel"  Id = 0x525
Stepping=5

Any ideas?
Cheers.

Mark Powell - System Administrator (UNIX) - Clifford Whitworth Building
A.I.S., University of Salford, Salford, Manchester, UK.
Tel: +44 161 295 5936  Fax: +44 161 295 5888  www.pgp.com for PGP key
M.S.Powell@ais.salfrd.ac.uk (spell salford correctly to reply to me)



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