From owner-freebsd-hackers Sun Aug 23 19:48:54 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id TAA05487 for freebsd-hackers-outgoing; Sun, 23 Aug 1998 19:48:54 -0700 (PDT) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from dan.emsphone.com (dan.emsphone.com [199.67.51.101]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id TAA05474 for ; Sun, 23 Aug 1998 19:48:48 -0700 (PDT) (envelope-from dan@dan.emsphone.com) Received: (from dan@localhost) by dan.emsphone.com (8.8.8/8.8.8) id VAA24537; Sun, 23 Aug 1998 21:48:01 -0500 (CDT) (envelope-from dan) Message-ID: <19980823214801.A24497@emsphone.com> Date: Sun, 23 Aug 1998 21:48:01 -0500 From: Dan Nelson To: David Kott , hackers@FreeBSD.ORG Subject: Re: Adaptec 1542i Performance on -stable [was Re: SCSI Controller] References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.94.2i In-Reply-To: ; from "David Kott" on Fri Aug 21 18:58:57 GMT 1998 X-OS: FreeBSD 2.2.7-STABLE Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG In the last episode (Aug 21), David Kott said: > I am using a 1542 right now on this -stable machine. While I am not > particularily overwhelmed by it's performance, I have had no problems > that I could definately link to the adapter itself. Perhaps I have not > configured it for optimal performance. > > root@kott [/root]# dd if=/dev/rsd0a of=/dev/null count=1024 > 1024+0 records in > 1024+0 records out > 524288 bytes transferred in 3.619458 secs (144853 bytes/sec) > > root@kott [/root]# dd if=/dev/rwd2s1a of=/dev/null count=1024 > 1024+0 records in > 1024+0 records out > 524288 bytes transferred in 0.173658 secs (3019083 bytes/sec) Try rerunning both dd lines with a bs=64k argument; the SCSI bus has a larger per-operation overhead then the IDE bus, and forcing it down to 512-byte transfer chunks isn't really a good benchmark. The 1542 support is quite good as far as I can tell; we use an old Compaq 486/66 and a 1542 as a tape drive machine, and I used to have a 1542 as my main SCSI controller until I got a 2940. -Dan Nelson dnelson@emsphone.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message