From owner-freebsd-stable@FreeBSD.ORG Thu Dec 29 21:56:52 2005 Return-Path: X-Original-To: freebsd-stable@freebsd.org Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 02B4516A41F for ; Thu, 29 Dec 2005 21:56:52 +0000 (GMT) (envelope-from mv@roq.com) Received: from p4.roq.com (ns1.ecoms.com [207.44.130.137]) by mx1.FreeBSD.org (Postfix) with ESMTP id 7A3A343D5A for ; Thu, 29 Dec 2005 21:56:51 +0000 (GMT) (envelope-from mv@roq.com) Received: from p4.roq.com (localhost.roq.com [127.0.0.1]) by p4.roq.com (Postfix) with ESMTP id 6072D4D0D8 for ; Thu, 29 Dec 2005 21:57:00 +0000 (GMT) Received: from [192.168.0.2] (ppp157-158.static.internode.on.net [150.101.157.158]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by p4.roq.com (Postfix) with ESMTP id B3B554D096 for ; Thu, 29 Dec 2005 21:56:59 +0000 (GMT) Message-ID: <43B45B9C.9030406@roq.com> Date: Fri, 30 Dec 2005 08:56:44 +1100 From: Michael Vince User-Agent: Mozilla/5.0 (X11; U; FreeBSD amd64; en-US; rv:1.7.12) Gecko/20051208 X-Accept-Language: en-us, en MIME-Version: 1.0 To: freebsd-stable@freebsd.org References: <43B2F0A8.2030609@freebsd.org> In-Reply-To: <43B2F0A8.2030609@freebsd.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: ClamAV using ClamSMTP Subject: Re: RELENG_6: Which scheduler for SMP? 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: Thu, 29 Dec 2005 21:56:52 -0000 Mark Ovens wrote: > I've never had any success with the ULE scheduler on my dual Athlon > box running RELENG_5; it was so unstable it made Windows 3.1 look > stable. In fact my current build, cvsup'd a couple of days ago, won't > even boot with ULE. > > From what I remember, ULE was intended to become the default scheduler > during the life of 5.0 but that hasn't happened. > > I've just cvsup'd the source for RELENG_6 and I'm surprised to find in > the GENERIC config file: > > #options SCHED_ULE # ULE scheduler > options SCHED_4BSD # 4BSD scheduler > > so it seems 4BSD is still the default scheduler. Is ULE _still_ > considered to be in development/experimental? Even the SMP config file > doesn't use ULE. > > Also in GENERIC: > > options PREEMPTION # Enable kernel thread preemption > > [....] > > options ADAPTIVE_GIANT # Giant mutex is adaptive. > > Yet in src/sys/conf/NOTES, ADAPTIVE_GIANT is listed under SMP Options > and PREEMPTION is listed under SMP Debugging Options which makes it > surprising that they are in the GENERIC config file. > > What I am trying to decide is whether there any point in making the > jump from a very stable RELENG_5 system to RELENG_6. AIUI the ULE > scheduler and it's associated options optimize the use of multiple > CPUs and by staying with 4BSD I'm not getting the best performance > from my system. > > Can anyone offer any advice on this please? > > The machine has dual Athlon MP2800s on a Asus A7M266-D mobo, 1Gbyte > ECC RAM and all SCSI disks and optical drives. > > I have been benchmarking a Java servlet under ULE, and I couldn't get result scores as high under ULE as I could under the regular the 4BSD (although it wasn't far off) and when I left the machine benchmarking all night under ULE I came back in the morning to find the machine unresponsive and in need of a hard reboot. Mike