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Date:      Mon, 8 Feb 1999 20:02:49 -0500 (EST)
From:      Chuck Robey <chuckr@mat.net>
To:        "William S. Duncanson" <caesar@starkreality.com>
Cc:        freebsd-smp@FreeBSD.ORG
Subject:   Re: Problems keeping time
Message-ID:  <Pine.BSF.4.05.9902082000290.338-100000@picnic.mat.net>
In-Reply-To: <4.1.19990208181440.03d1d4c0@fire.starkreality.com>

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On Mon, 8 Feb 1999, William S. Duncanson wrote:

> I just upgraded a FreeBSD box to a SMP system (basically, I swapped out the
> MB and added a processor).  Now, I'm having horrendous problems with the
> kernel clock drifting (it's running fast, about 7 seconds every 10
> minutes).  So far, xntpd seems to be keeping everything relatively close,
> but it's updating the clock every 10 minutes or so.  ntpq claims that all
> of the configured peers are "insane".  I'm pretty sure that this is a SMP
> issue, since it worked fine with a single processor (4.0-current).  So, the
> question is, how do I fix this?
> 
> Here's my kernel config.  I added the "CLK_USE_I8254_CALIBRATION" after I
> noticed the problem, but it doesn't appear to have fixed it:

I have a smp system too.  I've never had to use this method, but I
recall Poul-Henning talking about it, so I'll pass it on.  You can tweak
the method used to keep time via a sysctl:

sysctl -w kern.timecounter.method=1

I don't know more than that, you can either experiment (and let us know
if it worked) or wait for Poul-Henning to comment.

----------------------------+-----------------------------------------------
Chuck Robey                 | Interests include any kind of voice or data 
chuckr@glue.umd.edu         | communications topic, C programming, and Unix.
213 Lakeside Drive Apt T-1  |
Greenbelt, MD 20770         | I run picnic (FreeBSD-current)
(301) 220-2114              | and jaunt (Solaris7).
----------------------------+-----------------------------------------------





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