From owner-svn-src-stable@FreeBSD.ORG Wed Jun 5 13:30:52 2013 Return-Path: Delivered-To: svn-src-stable@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id 2301061A; Wed, 5 Jun 2013 13:30:52 +0000 (UTC) (envelope-from gibbs@scsiguy.com) Received: from aslan.scsiguy.com (aslan.scsiguy.com [70.89.174.89]) by mx1.freebsd.org (Postfix) with ESMTP id EEAF519B5; Wed, 5 Jun 2013 13:30:51 +0000 (UTC) Received: from [192.168.5.95] (ip-64-134-30-158.public.wayport.net [64.134.30.158]) (authenticated bits=0) by aslan.scsiguy.com (8.14.7/8.14.5) with ESMTP id r55DUmZu022024 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NO); Wed, 5 Jun 2013 13:30:50 GMT (envelope-from gibbs@scsiguy.com) References: <201306041047.r54AljAX050733@svn.freebsd.org> Mime-Version: 1.0 (1.0) In-Reply-To: <201306041047.r54AljAX050733@svn.freebsd.org> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Message-Id: <4A91EB3F-56FD-4E94-9981-0422032C9240@scsiguy.com> X-Mailer: iPhone Mail (10B329) From: "Justin T. Gibbs" Subject: Re: svn commit: r251372 - in stable/9/sys/cam: ata scsi Date: Wed, 5 Jun 2013 06:30:44 -0700 To: Steven Hartland X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.4.3 (aslan.scsiguy.com [70.89.174.89]); Wed, 05 Jun 2013 13:30:50 +0000 (UTC) Cc: "svn-src-stable@freebsd.org" , "svn-src-all@freebsd.org" , "src-committers@freebsd.org" , "svn-src-stable-9@freebsd.org" X-BeenThere: svn-src-stable@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: SVN commit messages for all the -stable branches of the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 05 Jun 2013 13:30:52 -0000 On Jun 4, 2013, at 3:47, Steven Hartland wrote: > Author: smh > Date: Tue Jun 4 10:47:44 2013 > New Revision: 251372 > URL: http://svnweb.freebsd.org/changeset/base/251372 >=20 > Log: > Enhanced BIO_DELETE support for CAM SCSI to add ATA_TRIM support. >=20 > Disable CAM BIO queue sorting for non-rotating media by default. Using the elevator makes perfect sense even for random access devices when o= perations can be merged. Even SSDs have fixed, per-command overheads and mer= ging writes may help prevent fragmentation. On drivers that support unmappe= d I/O, merging should be fairly cheap. It would be an interesting performance experiment. >=20 -- Justin=