From owner-freebsd-stable@FreeBSD.ORG Tue Dec 2 12:41:05 2008 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 31368106564A for ; Tue, 2 Dec 2008 12:41:05 +0000 (UTC) (envelope-from dkelly@hiwaay.net) Received: from smtp.knology.net (smtp.knology.net [24.214.63.101]) by mx1.freebsd.org (Postfix) with ESMTP id BDE588FC17 for ; Tue, 2 Dec 2008 12:41:04 +0000 (UTC) (envelope-from dkelly@hiwaay.net) Received: (qmail 26689 invoked by uid 0); 2 Dec 2008 12:14:21 -0000 Received: from unknown (HELO ?10.0.0.187?) (75.76.211.79) by smtp5.knology.net with SMTP; 2 Dec 2008 12:14:21 -0000 In-Reply-To: <4934CB77.30906@transactionware.com> References: <2515BCEE3A2F4CBA8FFB9F1C052924AA@jmlaptop> <4934CB77.30906@transactionware.com> Mime-Version: 1.0 (Apple Message framework v753.1) Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Message-Id: <34C71E28-F128-4F83-80EF-75768172A59D@hiwaay.net> Content-Transfer-Encoding: 7bit From: David Kelly Date: Tue, 2 Dec 2008 06:14:20 -0600 To: Jan Mikkelsen X-Mailer: Apple Mail (2.753.1) Cc: freebsd-stable@freebsd.org Subject: Re: 7.1-PRERELEASE: arcmsr write performance problem X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: freebsd-stable@freebsd.org List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 02 Dec 2008 12:41:05 -0000 On Dec 1, 2008, at 11:45 PM, Jan Mikkelsen wrote: > Replying to my own post ... > > I have done a test on the same machine comparing 6.3-p1 to 7.1- > PRE. The performance is the expected ~6MB/s (because of the lack > of cache) on 6.3-p1, so the BIOS change doesn't seem to be at fault. > > This seems to be a regression somewhere between 6.3 to 7.1. The > Areca driver is the same in 6.3 and 7.1, so the problem seems to be > elsewhere. > > I think this is more than just a "performance" problem. The > observations with gstat showing extremely high ms/w values (I have > seen them as high as 22000) makes it look like IO completion > interrupts are being lost. > > Any suggestions on where to look next? Are there obvious candidates? ATA maximum block transfer has dropped from 128k to 64k in 7.x. Am not sure where the handle is to tweak it back up but has slowed peak thruput on my Dell PE400SC. Can watch with "systat -v" Worse, I have a stripped array of 2 drives that won't transfer more than 43k at a chunk because apparently the stripe metadata didn't align nicely on 64k multiples. -- David Kelly N4HHE, dkelly@HiWAAY.net ======================================================================== Whom computers would destroy, they must first drive mad.