From owner-freebsd-current@FreeBSD.ORG Tue Feb 17 06:21:21 2009 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 358AC1065674 for ; Tue, 17 Feb 2009 06:21:21 +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 657168FC14 for ; Tue, 17 Feb 2009 06:21:20 +0000 (UTC) (envelope-from janm@transactionware.com) Received: (qmail 25323 invoked from network); 17 Feb 2009 05:54:59 -0000 Received: from midgard.transactionware.com (192.168.1.55) by dm.transactionware.com with SMTP; 17 Feb 2009 05:54:59 -0000 Received: (qmail 1668 invoked by uid 907); 17 Feb 2009 05:54:36 -0000 Received: from jmdesktop.transactionware.com (HELO [192.168.1.32]) (192.168.1.32) by midgard.transactionware.com (qpsmtpd/0.40) with ESMTP; Tue, 17 Feb 2009 16:54:36 +1100 Message-ID: <499A5122.1070605@transactionware.com> Date: Tue, 17 Feb 2009 16:54:42 +1100 From: Jan Mikkelsen User-Agent: Thunderbird 2.0.0.19 (Windows/20081209) MIME-Version: 1.0 To: Scott Long References: <499551B9.7050805@samsco.org> In-Reply-To: <499551B9.7050805@samsco.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Mailman-Approved-At: Tue, 17 Feb 2009 12:26:16 +0000 Cc: FreeBSD Current , FreeBSD Stable Subject: Re: HEADS UP: Major CAM performance regression X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 17 Feb 2009 06:21:21 -0000 Hi Scott, I just tried this on 7.1-p2 with an Areca (arcmsr) controller with SATA drives attached to see if it fixed the performance problem I noticed back in December 2008. See: http://docs.freebsd.org/cgi/getmsg.cgi?fetch=43971+0+archive/2008/freebsd-stable/20081207.freebsd-stable The performance is still terrible. Interestingly, running your camcontrol command returns "device openings" of 1 on 7.1, and 255 on 6.4, so it seems to be the same underlying problem. I am happy to try other patches. Thanks, Jan Mikkelsen Scott Long wrote: > All, > > A major performance regression was introduced to the CAM subsystem in > FreeBSD 7.1. The following configurations are known to be affected: > > VMWare ESX > VMWare Fusion > (using bt or lsilogic controller options) > HP CISS RAID > Some MPT-SAS combinations with SATA drives attached > (Includes Dell SAS5/ir, but not PERC5/PERC6). > > Pure SCSI and SAS subsystems likely are NOT affected. Any hardware > that uses the 'ata' driver is also definitely NOT affected. To > determine if your installation is affected, run the following command as > root: > > camcontrol tags da0 > > Substitute 'da0' with another appropriate drive device number, if > needed. Note that this ONLY AFFECTS 'da' DEVICES. If your disks are > 'ad' devices, they are NOT affected. > > The result from running this command should be an output similar to the > following: > > (pass0:mpt0:0:8:0): device openings: 255 > > If, instead, it reports a value of '1', you are likely affected. Note > that it may be normal for USB memory devices to report a low number. > Also, many legacy SCSI disks, and devices that are not disks, may also > be expected to report a low number. > > The effect of this problem is that only one I/O command will be issued > to the controller and disk at a time, instead of overlapping multiple > commands in parallel. This causes significantly higher latency in > servicing moderate and heavy I/O workloads, leading to very poor > performance. Performance can be easily compared by downgrading to > FreeBSD 7.0. > > I have committed a fix for this problem for FreeBSD 8-CURRENT as of SVN > revision 188570. FreeBSD 7-STABLE will be updated with the fix in a few > days once I've gotten confirmation that the fix works and doesn't cause > any adverse side-effects. Anyone wanting to help in this validation > effort should apply the attached patch to their kernel source tree and > recompile. Please contact me directly by email to report if the problem > is fixed for you. > > If the validation process goes smoothly, I will work with the release > engineering team to turn this fix into an official errata update for > FreeBSD 7.1. > > Thanks in advance for your help. > > Scott > > > > > ------------------------------------------------------------------------ > > _______________________________________________ > freebsd-stable@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org"