From owner-freebsd-stable@FreeBSD.ORG Wed Dec 14 16:59:53 2011 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id D732A1065676; Wed, 14 Dec 2011 16:59:53 +0000 (UTC) (envelope-from mike@sentex.net) Received: from smarthost1.sentex.ca (smarthost1-6.sentex.ca [IPv6:2607:f3e0:0:1::12]) by mx1.freebsd.org (Postfix) with ESMTP id 919838FC19; Wed, 14 Dec 2011 16:59:53 +0000 (UTC) Received: from [IPv6:2607:f3e0:0:4:f025:8813:7603:7e4a] (saphire3.sentex.ca [IPv6:2607:f3e0:0:4:f025:8813:7603:7e4a]) by smarthost1.sentex.ca (8.14.5/8.14.4) with ESMTP id pBEGxlPE000375; Wed, 14 Dec 2011 11:59:47 -0500 (EST) (envelope-from mike@sentex.net) Message-ID: <4EE8D607.1000504@sentex.net> Date: Wed, 14 Dec 2011 11:59:51 -0500 From: Mike Tancsa Organization: Sentex Communications User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.13) Gecko/20101207 Thunderbird/3.1.7 MIME-Version: 1.0 To: mdf@freebsd.org References: <4EE1EAFE.3070408@m5p.com> <4EE22421.9060707@gmail.com> <4EE6060D.5060201@mail.zedat.fu-berlin.de> <4EE69C5A.3090005@FreeBSD.org> <20111213104048.40f3e3de@nonamehost.> <20111213230441.GB42285@stack.nl> <4ee7e2d3.0a3c640a.4617.4a33SMTPIN_ADDED@mx.google.com> In-Reply-To: X-Enigmail-Version: 1.1.1 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.71 on IPv6:2607:f3e0:0:1::12 Cc: Ivan Klymenko , Doug Barton , freebsd-stable@freebsd.org, Jilles Tjoelker , "O. Hartmann" , Current FreeBSD , freebsd-performance@freebsd.org Subject: Re: SCHED_ULE should not be the default X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 14 Dec 2011 16:59:54 -0000 On 12/13/2011 7:01 PM, mdf@freebsd.org wrote: > > Has anyone experiencing problems tried to set sysctl kern.sched.steal_thresh=1 ? > > I don't remember what our specific problem at $WORK was, perhaps it > was just interrupt threads not getting serviced fast enough, but we've > hard-coded this to 1 and removed the code that sets it in > sched_initticks(). The same effect should be had by setting the > sysctl after a box is up. FWIW, this does impact the performance of pbzip2 on an i7. Using a 1.1G file pbzip2 -v -c big > /dev/null with burnP6 running in the background, sysctl kern.sched.steal_thresh=1 vs sysctl kern.sched.steal_thresh=3 N Min Max Median Avg Stddev x 10 38.005022 38.42238 38.194648 38.165052 0.15546188 + 9 38.695417 40.595544 39.392127 39.435384 0.59814114 Difference at 95.0% confidence 1.27033 +/- 0.412636 3.32852% +/- 1.08119% (Student's t, pooled s = 0.425627) a value of 1 is *slightly* faster. -- ------------------- Mike Tancsa, tel +1 519 651 3400 Sentex Communications, mike@sentex.net Providing Internet services since 1994 www.sentex.net Cambridge, Ontario Canada http://www.tancsa.com/