From owner-cvs-src@FreeBSD.ORG Sun Apr 15 23:11:19 2007 Return-Path: X-Original-To: cvs-src@FreeBSD.org Delivered-To: cvs-src@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 3788B16A401; Sun, 15 Apr 2007 23:11:19 +0000 (UTC) (envelope-from scottl@samsco.org) Received: from pooker.samsco.org (pooker.samsco.org [168.103.85.57]) by mx1.freebsd.org (Postfix) with ESMTP id BE6A013C469; Sun, 15 Apr 2007 23:11:17 +0000 (UTC) (envelope-from scottl@samsco.org) Received: from phobos.samsco.home (phobos.samsco.home [192.168.254.11]) (authenticated bits=0) by pooker.samsco.org (8.13.8/8.13.8) with ESMTP id l3FNBA08019128; Sun, 15 Apr 2007 17:11:10 -0600 (MDT) (envelope-from scottl@samsco.org) Message-ID: <4622B0FD.9000400@samsco.org> Date: Sun, 15 Apr 2007 17:10:53 -0600 From: Scott Long User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en-US; rv:1.8.1.2pre) Gecko/20070111 SeaMonkey/1.1 MIME-Version: 1.0 To: Nate Lawson References: <20070415084926.C77C816A521@hub.freebsd.org> <462260B7.8090602@root.org> In-Reply-To: <462260B7.8090602@root.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH authentication, not delayed by milter-greylist-2.0.2 (pooker.samsco.org [168.103.85.57]); Sun, 15 Apr 2007 17:11:10 -0600 (MDT) X-Spam-Status: No, score=-0.8 required=5.5 tests=ALL_TRUSTED,SUBJ_HAS_SPACES autolearn=failed version=3.1.8 X-Spam-Checker-Version: SpamAssassin 3.1.8 (2007-02-13) on pooker.samsco.org Cc: cvs-src@FreeBSD.org, src-committers@FreeBSD.org, Scott Long , cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/cam cam_ccb.h cam_periph.c cam_periph.h cam_sim.c cam_sim.h cam_xpt.c cam_xpt.h cam_xpt_periph.h src/sys/cam/scsi scsi_cd.c scsi_ch.c scsi_da.c scsi_low.c scsi_pass.c scsi_pt.c scsi_sa.c scsi_ses.c scsi_sg.c ... X-BeenThere: cvs-src@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: CVS commit messages for the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 15 Apr 2007 23:11:19 -0000 Nate Lawson wrote: [...] > > Amazing work, I owe you a beer for following through where none of us > did. I see you went with the SIM lock approach, which seems reasonable. I was surprised when I measured the contention on the SIM lock. It was much lower than I expected it to be. So this approach is looking to be pretty good. It can be improved a little bit in CAM, but the focus will now be on efficient locking strategies for the drivers. I have simple locking implementations for MPT, AHC, and AHD right now, and I'll have CISS and maybe SYM shortly. I suspect that the easiest approach to an efficient strategy will be to make the driver ithreads be a lock-free as possible. I'm planning on writing a few pages of design docs on this in the next few days to give people a guide for locking down their drivers. Scott