From owner-freebsd-current@FreeBSD.ORG  Fri Aug 15 23:57:01 2003
Return-Path: <owner-freebsd-current@FreeBSD.ORG>
Delivered-To: freebsd-current@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id C325B37B401
	for <freebsd-current@freebsd.org>;
	Fri, 15 Aug 2003 23:57:01 -0700 (PDT)
Received: from stork.mail.pas.earthlink.net (stork.mail.pas.earthlink.net
	[207.217.120.188])
	by mx1.FreeBSD.org (Postfix) with ESMTP id 2A5C143FB1
	for <freebsd-current@freebsd.org>;
	Fri, 15 Aug 2003 23:57:01 -0700 (PDT)
	(envelope-from tlambert2@mindspring.com)
Received: from user-2ivflb5.dialup.mindspring.com ([165.247.213.101]
	helo=mindspring.com)
	by stork.mail.pas.earthlink.net with asmtp (SSLv3:RC4-MD5:128)
	(Exim 3.33 #1)	id 19nuze-0003Wj-00; Fri, 15 Aug 2003 23:56:55 -0700
Message-ID: <3F3DD57F.5848FD64@mindspring.com>
Date: Fri, 15 Aug 2003 23:55:59 -0700
From: Terry Lambert <tlambert2@mindspring.com>
X-Mailer: Mozilla 4.79 [en] (Win98; U)
X-Accept-Language: en
MIME-Version: 1.0
To: Thorsten Greiner <thorsten.greiner@web.de>
References: <11229.1060970608@critter.freebsd.dk>
	<1060978640.603.11.camel@localhost> <20030815205047.GA719@tybalt>
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
X-ELNK-Trace: b1a02af9316fbb217a47c185c03b154d40683398e744b8a4dec075ab57d3ce0dded3fb48c7c5959393caf27dac41a8fd350badd9bab72f9c350badd9bab72f9c
cc: Poul-Henning Kamp <phk@phk.freebsd.dk>
cc: freebsd-current@FreeBSD.org
cc: MATOBA Hirozumi <matoba@st.rim.or.jp>
cc: nate@root.org
Subject: Re: clock works slowly when I change CPU speed
X-BeenThere: freebsd-current@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: Discussions about the use of FreeBSD-current
	<freebsd-current.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>,
	<mailto:freebsd-current-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-current>
List-Post: <mailto:freebsd-current@freebsd.org>
List-Help: <mailto:freebsd-current-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>,
	<mailto:freebsd-current-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sat, 16 Aug 2003 06:57:02 -0000

Thorsten Greiner wrote:
> * Bob Fleck <bob@securesoftware.com> [2003-08-15 22:46]:
> > So, what should be done to restore the proper behavior of the
> > timekeeping on these systems?
> 
> $ dmesg | grep counter
> Timecounter "i8254"  frequency 1193182 Hz
> Timecounter "ACPI-fast"  frequency 3579545 Hz
> Timecounter "TSC"  frequency 1595302164 Hz
> $ sysctl -w kern.timecounter.hardware=i8254
> 
> Fixes the problem for me. I suspect you should set this in
> /etc/sysctl.conf to enable it permanently.

I suspect that systems where ACPI indicates that the clock speed
may change as a result of power management events should set this
automatically so people don't have to hack up their system with
sysctl's just to get things to work, when it's well known that
the system selecting TSC by default on systems with a variable
processor speed will experience problems otherwise.

I'm guessing what changes in the patches is that the default for
preferred clock changed to the wrong thing.

-- Terry