From owner-freebsd-hackers Wed Nov 11 11:02:38 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id LAA20628 for freebsd-hackers-outgoing; Wed, 11 Nov 1998 11:02:38 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from pluto.plutotech.com (mail.plutotech.com [206.168.67.137]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id LAA20622 for ; Wed, 11 Nov 1998 11:02:35 -0800 (PST) (envelope-from gibbs@plutotech.com) Received: from narnia.plutotech.com (narnia.plutotech.com [206.168.67.130]) by pluto.plutotech.com (8.8.7/8.8.5) with ESMTP id MAA04591; Wed, 11 Nov 1998 12:00:41 -0700 (MST) Message-Id: <199811111900.MAA04591@pluto.plutotech.com> X-Mailer: exmh version 2.0.2 2/24/98 To: Mike Smith cc: "Justin T. Gibbs" , Greg Lehey , hackers@FreeBSD.ORG Subject: Re: SCSI vs. DMA33.. In-reply-to: Your message of "Wed, 11 Nov 1998 10:08:08 PST." <199811111808.KAA04141@dingo.cdrom.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Wed, 11 Nov 1998 11:53:55 -0700 From: "Justin T. Gibbs" Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG >Unfortunately, Simon's numbers tend to indicate that CAM doesn't >provide the same order of magnitude improvement that the old SCSI >subsystem did. At least it's a little more robust. 8) I never said it was order of magnitude improvement only an order of magnitude increase in concurrency. The numbers I've seen is on the order of 50% to 100% change in performance. Simon's benchmark is hitting the O(N) constraint of bufqdisksort which I'll fix as soon as I get a chance. I never received numbers from him with a change to remove the kernel elevator sort, but I would expect to see an improvement in scalability. -- Justin To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message