From owner-freebsd-stable@FreeBSD.ORG Wed Dec 3 04:05:55 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 C49F61065670 for ; Wed, 3 Dec 2008 04:05:55 +0000 (UTC) (envelope-from janm@transactionware.com) Received: from mail.transactionware.com (mail.transactionware.com [203.14.245.7]) by mx1.freebsd.org (Postfix) with SMTP id 255B28FC08 for ; Wed, 3 Dec 2008 04:05:54 +0000 (UTC) (envelope-from janm@transactionware.com) Received: (qmail 37677 invoked from network); 3 Dec 2008 04:06:14 -0000 Received: from midgard.transactionware.com (192.168.1.55) by dm.transactionware.com with SMTP; 3 Dec 2008 04:06:14 -0000 Received: (qmail 3282 invoked by uid 907); 3 Dec 2008 04:05:50 -0000 Received: from [192.168.1.32] (HELO [192.168.1.32]) (192.168.1.32) by midgard.transactionware.com (qpsmtpd/0.40) with ESMTP; Wed, 03 Dec 2008 15:05:50 +1100 Message-ID: <4936059E.4050905@transactionware.com> Date: Wed, 03 Dec 2008 15:05:50 +1100 From: Jan Mikkelsen User-Agent: Thunderbird 2.0.0.18 (Windows/20081105) MIME-Version: 1.0 To: freebsd-stable@freebsd.org References: <2515BCEE3A2F4CBA8FFB9F1C052924AA@jmlaptop> <4934CB77.30906@transactionware.com> <34C71E28-F128-4F83-80EF-75768172A59D@hiwaay.net> In-Reply-To: <34C71E28-F128-4F83-80EF-75768172A59D@hiwaay.net> Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: 7.1-PRERELEASE: arcmsr write performance problem X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 03 Dec 2008 04:05:55 -0000 David Kelly wrote: > > 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" Interesting, thanks. > 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. I know the partitions start at 64kB multiples in my case. I did, however, reduce the RAID-6 stripe size to 4kB (from 64kB) and that improved things slightly, but the throughput on 7.1 is still slower by about a factor of a about 6 (measured by untaring ~3GB across ~167k files into a fresh filesystem). And on 7.1 the machine is unusable during much of the time. > -- > David Kelly N4HHE, dkelly@HiWAAY.net > ======================================================================== > Whom computers would destroy, they must first drive mad.