From owner-svn-src-head@FreeBSD.ORG Wed Mar 3 21:15:36 2010 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 68EE01065676; Wed, 3 Mar 2010 21:15:36 +0000 (UTC) (envelope-from bra@fsn.hu) Received: from people.fsn.hu (people.fsn.hu [195.228.252.137]) by mx1.freebsd.org (Postfix) with ESMTP id 4DED18FC0A; Wed, 3 Mar 2010 21:15:34 +0000 (UTC) Received: by people.fsn.hu (Postfix, from userid 1001) id 724602265B7; Wed, 3 Mar 2010 22:08:07 +0100 (CET) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MF-ACE0E1EA [pR: 19.6456] X-CRM114-CacheID: sfid-20100303_22080_88285453 X-CRM114-Status: Good ( pR: 19.6456 ) Message-ID: <4B8ECFB5.3040902@fsn.hu> Date: Wed, 03 Mar 2010 22:08:05 +0100 From: Attila Nagy User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.1.23) Gecko/20090817 Thunderbird/2.0.0.23 Mnenhy/0.7.6.0 MIME-Version: 1.0 To: Alexander Motin References: <201003031758.o23HwfnD023194@svn.freebsd.org> <4B8EC54E.4050705@fsn.hu> <4B8EC9E0.6050703@FreeBSD.org> In-Reply-To: <4B8EC9E0.6050703@FreeBSD.org> X-Stationery: 0.4.10 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.2.3 (people.fsn.hu); Wed, 03 Mar 2010 22:08:06 +0100 (CET) Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r204648 - head/sys/dev/ciss X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 03 Mar 2010 21:15:36 -0000 Alexander Motin wrote: > Attila Nagy wrote: > >> Alexander Motin wrote: >> >>> Author: mav >>> Date: Wed Mar 3 17:58:41 2010 >>> New Revision: 204648 >>> URL: http://svn.freebsd.org/changeset/base/204648 >>> >>> Log: >>> Several changes to fix livelock under high load, introduced by r203489: >>> - change the way in which command queue overflow is handled; >>> - do not expose to CAM two command slots, used for driver's internal purposes; >>> - allow driver to use up to 1024 command slots, instead of 256 before. >>> >>> >> Thank you for hunting this bug down. Do you plan to increase the maximum >> logical device limit as well? >> > > Not sure. I just have no idea why this limitation was enforced. Even if > I personally don't see problems from increasing it, it would be nice if > somebody more aware of this driver tell whether it is correct for all > supported hardware. I just don't have any. Thank you for provided > access. If nobody responds, we may try our luck in CURRENT. > >From the VCS history it seems this limit is there from the very first revision, which was made for the Compaq SmartRAID 5* line. Those were parallel SCSI controllers, so 15 was a sane value there (you couldn't attach more than 15 devices to the bus). The change came with the new SAS controllers, which can have external connectors, so a lot of drives (and logical drives) can be attached to them. I use SAS (P800) controllers with increased limit without any ill effects, but can try older ones (SCSI: 5i, 6i) too if needed.