From owner-freebsd-questions@FreeBSD.ORG Wed Jul 6 17:01:33 2011 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 103B2106566C; Wed, 6 Jul 2011 17:01:33 +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 E2C888FC08; Wed, 6 Jul 2011 17:01:32 +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 p66H1W9s068818; Wed, 6 Jul 2011 10:01:32 -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 p66H1Wgc068817; Wed, 6 Jul 2011 10:01:32 -0700 (PDT) (envelope-from sgk) Date: Wed, 6 Jul 2011 10:01:32 -0700 From: Steve Kargl To: "Hartmann, O." Message-ID: <20110706170132.GA68775@troutmask.apl.washington.edu> References: <4E1421D9.7080808@zedat.fu-berlin.de> <4E147F54.40908@zedat.fu-berlin.de> <20110706162811.GA68436@troutmask.apl.washington.edu> <4E148F7F.5020209@zedat.fu-berlin.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4E148F7F.5020209@zedat.fu-berlin.de> User-Agent: Mutt/1.4.2.3i Cc: FreeBSD Current , arrowdodger <6yearold@gmail.com>, freebsd-questions@freebsd.org Subject: Re: Heavy I/O blocks FreeBSD box for several seconds X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 06 Jul 2011 17:01:33 -0000 On Wed, Jul 06, 2011 at 06:38:23PM +0200, Hartmann, O. wrote: > On 07/06/11 18:28, Steve Kargl wrote: > >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 > > > > Worth a try, > but most of my code I use is OpenMP, not MPI. It may impact OpenMP. I don't have any OpenMP to test. But, if OpenMP is spawning as many or more threads than the number of available processors/cores, then I think you will have problems. > The post is of 2008, that's three years ago and 9.0 is on the brink to > become released ... I periodically ran the same type test in the 2008 post over the last three years. Nothing has changed. I even set up an account on one node in my cluster for jeffr to use. He was too busy to investigate at that time. -- Steve