From owner-freebsd-questions@FreeBSD.ORG Fri Mar 11 03:10:57 2005 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 8CE7016A4CE for ; Fri, 11 Mar 2005 03:10:57 +0000 (GMT) Received: from ms-smtp-04-eri0.southeast.rr.com (ms-smtp-04-lbl.southeast.rr.com [24.25.9.103]) by mx1.FreeBSD.org (Postfix) with ESMTP id EE3BB43D46 for ; Fri, 11 Mar 2005 03:10:53 +0000 (GMT) (envelope-from jason@ec.rr.com) Received: from BARTON (cpe-065-184-201-054.ec.rr.com [65.184.201.54]) j2B3AhCh024653; Thu, 10 Mar 2005 22:10:43 -0500 (EST) Date: Fri, 11 Mar 2005 03:19:11 +0000 From: Jason Henson To: freebsd-questions@freebsd.org Cc: freebsd-questions@freebsd.org References: <1258079440.20050311032403@wanadoo.fr> In-Reply-To: <1258079440.20050311032403@wanadoo.fr> (from atkielski.anthony@wanadoo.fr on Thu Mar 10 21:24:03 2005) X-Mailer: Balsa 2.2.6 Message-Id: <1110511151l.2443l.0l@BARTON> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; DelSp=Yes; Format=Flowed Content-Disposition: inline Content-Transfer-Encoding: quoted-printable X-Virus-Scanned: Symantec AntiVirus Scan Engine Subject: Re: Timer setting in FreeBSD X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 11 Mar 2005 03:10:57 -0000 On 03/10/05 21:24:03, Anthony Atkielski wrote: > I was reading that recent versions of Linux have increased the base > timer rate (for scheduling and other purposes) from 100 Hz to 1000 =20 > Hz. > I note that FreeBSD apparently will increase this in the same way in > 6.x. >=20 > Is there a way to adjust this value (by configuration, modifying > source, > sysctl, etc.)? Can it be done on a running system? If it can be > changed, are there any significant reasons for adjusting it, and what > are the pros and cons? >=20 > Having 1000 interrupts per second just to keep track of the time =20 > seems > excessive to me in most configurations. Does anyone know how long > this > interrupt takes to service under FreeBSD with specific processors? >=20 > -- > Anthony >=20 >=20 > _______________________________________________ man polling, this is what I use to get the best possible even division =20 with the "Timecounter "i8254" frequency 1193182 Hz quality 0". add something like this to the kernel config. options HZ=3D2299 options DEVICE_POLLING Also you should search the archives first, there is plenty of info on =20 this there. Things like 10000 is a good setting for gigbit ethernet =20 cards, and not needed at all with some network cards that have some =20 hardware/driver combonation that does this automatically. I think the =20 fxp cards do it, and adding polling to fxp cards hurt performance =20 alittle.