From owner-freebsd-stable Mon Jul 16 8: 0:55 2001 Delivered-To: freebsd-stable@freebsd.org Received: from quack.kfu.com (quack.kfu.com [205.178.90.194]) by hub.freebsd.org (Postfix) with ESMTP id C92D937B405 for ; Mon, 16 Jul 2001 08:00:51 -0700 (PDT) (envelope-from nsayer@quack.kfu.com) Received: from morpheus.kfu.com (morpheus.kfu.com [3ffe:1200:301b:1:2d0:b7ff:fe3f:bdd0]) by quack.kfu.com (8.11.3/8.11.3) with ESMTP id f6GF0hJ02786 (using TLSv1/SSLv3 with cipher EDH-RSA-DES-CBC3-SHA (168 bits) verified OK); Mon, 16 Jul 2001 08:00:48 -0700 (PDT) (envelope-from nsayer@quack.kfu.com) Received: from quack.kfu.com (localhost [127.0.0.1]) by morpheus.kfu.com (8.11.4/8.11.4) with ESMTP id f6GF0hC02475; Mon, 16 Jul 2001 08:00:43 -0700 (PDT) (envelope-from nsayer@quack.kfu.com) Message-ID: <3B53019A.5080902@quack.kfu.com> Date: Mon, 16 Jul 2001 08:00:42 -0700 From: Nick Sayer User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:0.9.2) Gecko/20010701 X-Accept-Language: en, en-US, en-GB MIME-Version: 1.0 To: Lamont Granquist Cc: Bruce Burden , freebsd-stable@FreeBSD.ORG Subject: Re: Regarding New FreeBSD BenchMark From Sysadmin Mag (left out a fiew tuning options) References: <20010713235530.W12542-100000@coredump.scriptkiddie.org> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Lamont Granquist wrote: > i've got: > > ahc0: port 0xcc00-0xccff mem 0xefffe000-0xefffefff irq 11 at device 13.0 on pci0 > aic7899: Wide Channel A, SCSI Id=7, 32/255 SCBs > ahc1: port 0xdc00-0xdcff mem 0xeffff000-0xefffffff irq 10 at device 13.1 on pci0 > aic7899: Wide Channel B, SCSI Id=7, 32/255 SCBs > > and: > > da0 at ahc0 bus 0 target 0 lun 0 > da0: Fixed Direct Access SCSI-3 device > da0: 160.000MB/s transfers (80.000MHz, offset 63, 16bit), Tagged Queueing Enabled > da0: 35003MB (71687369 512 byte sectors: 255H 63S/T 4462C) > > and WCE was = 1 by default, but camcontrol worked to turn it off > I could be wrong, but my understanding is that tag queueing is a form of write caching, but all it does is allow the drive to reorder the writes. Unlike the evil form of write caching, the OS is given true completion notice, which is what makes it OK. So if you have tag queueing, you should leave write caching on. This is only possible on SCSI drives and certain very new IBM ATA disks. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message