From owner-freebsd-current@FreeBSD.ORG  Mon Jul 12 19:39:14 2004
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 2BDCA16A4CE
	for <freebsd-current@freebsd.org>;
	Mon, 12 Jul 2004 19:39:14 +0000 (GMT)
Received: from fledge.watson.org (fledge.watson.org [204.156.12.50])
	by mx1.FreeBSD.org (Postfix) with ESMTP id DB37E43D31
	for <freebsd-current@freebsd.org>;
	Mon, 12 Jul 2004 19:39:13 +0000 (GMT)
	(envelope-from robert@fledge.watson.org)
Received: from fledge.watson.org (localhost [127.0.0.1])
	by fledge.watson.org (8.12.11/8.12.11) with ESMTP id i6CJd1qt051592;
	Mon, 12 Jul 2004 15:39:01 -0400 (EDT)
	(envelope-from robert@fledge.watson.org)
Received: from localhost (robert@localhost)i6CJd1Pv051589;
	Mon, 12 Jul 2004 15:39:01 -0400 (EDT)
	(envelope-from robert@fledge.watson.org)
Date: Mon, 12 Jul 2004 15:39:01 -0400 (EDT)
From: Robert Watson <rwatson@freebsd.org>
X-Sender: robert@fledge.watson.org
To: Arjan van Leeuwen <avleeuwen@piwebs.com>
In-Reply-To: <opsa1homcv3qdyu1@localhost>
Message-ID: <Pine.NEB.3.96L.1040712153808.34546D-100000@fledge.watson.org>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
cc: "freebsd-current@freebsd.org" <freebsd-current@freebsd.org>
cc: Ariff Abdullah <skywizard@mybsd.org.my>
Subject: Re: Native preemption is the culprit [was Re: today's CURRENT
	lockups]
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: Mon, 12 Jul 2004 19:39:14 -0000


On Mon, 12 Jul 2004, Arjan van Leeuwen wrote:

> > I tried to upgrade my kernel from 5.2.1 to -CURRENT and cvsupped
> > post-preemption. Running a UP-Kernel on a UP-Machine with either
> > SCHED_ULE or SCHED_BSD froze the machine under heavy load. It doesn't
> > survive a buildworld or a medium port-build.
> 
> Same here. 

Per my earlier post, I've experienced similar unreliability.  The work
around I'm using is to build with "#define PREEMPTION" from param.h
disabled.  This results in a quite usable kernel, although quite probably
more poor interrupt handling latency, etc.

Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
robert@fledge.watson.org      Principal Research Scientist, McAfee Research