From owner-freebsd-current@FreeBSD.ORG  Wed Jul  6 16:28:12 2011
Return-Path: <owner-freebsd-current@FreeBSD.ORG>
Delivered-To: freebsd-current@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 474CC1065675;
	Wed,  6 Jul 2011 16:28:12 +0000 (UTC)
	(envelope-from sgk@troutmask.apl.washington.edu)
Received: from troutmask.apl.washington.edu (troutmask.apl.washington.edu
	[128.95.76.21])
	by mx1.freebsd.org (Postfix) with ESMTP id 279F38FC1B;
	Wed,  6 Jul 2011 16:28:12 +0000 (UTC)
Received: from troutmask.apl.washington.edu (localhost.apl.washington.edu
	[127.0.0.1])
	by troutmask.apl.washington.edu (8.14.4/8.14.4) with ESMTP id
	p66GSBxi068608; Wed, 6 Jul 2011 09:28:11 -0700 (PDT)
	(envelope-from sgk@troutmask.apl.washington.edu)
Received: (from sgk@localhost)
	by troutmask.apl.washington.edu (8.14.4/8.14.4/Submit) id
	p66GSBCU068607; Wed, 6 Jul 2011 09:28:11 -0700 (PDT)
	(envelope-from sgk)
Date: Wed, 6 Jul 2011 09:28:11 -0700
From: Steve Kargl <sgk@troutmask.apl.washington.edu>
To: "O. Hartmann" <ohartman@zedat.fu-berlin.de>
Message-ID: <20110706162811.GA68436@troutmask.apl.washington.edu>
References: <4E1421D9.7080808@zedat.fu-berlin.de>
	<CALH631=F4bSgNDE4w0qcXGMgGxZRRwCP9n-H4M0c+1UEaqWr7Q@mail.gmail.com>
	<4E147F54.40908@zedat.fu-berlin.de>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <4E147F54.40908@zedat.fu-berlin.de>
User-Agent: Mutt/1.4.2.3i
Cc: FreeBSD Current <freebsd-current@freebsd.org>,
	arrowdodger <6yearold@gmail.com>, freebsd-questions@freebsd.org
Subject: Re: Heavy I/O blocks FreeBSD box for several seconds
X-BeenThere: freebsd-current@freebsd.org
X-Mailman-Version: 2.1.5
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: Wed, 06 Jul 2011 16:28:12 -0000

On Wed, Jul 06, 2011 at 05:29:24PM +0200, O. Hartmann wrote:
> 
> I use SCHED_ULE on all machines, since it is supposed to be performing 
> better on multicore boxes, but there are lots of suggestions switching 
> back to the old SCHED_4BSD scheduler.
> 

If you are using MPI in numerical codes, then you want
to use SCHED_4BSD.  I've posted numerous times about ULE
and its very poor performance when using MPI.

http://lists.freebsd.org/pipermail/freebsd-hackers/2008-October/026375.html

-- 
Steve