From owner-freebsd-scsi@freebsd.org Wed Aug 5 18:14:32 2015 Return-Path: Delivered-To: freebsd-scsi@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 22CA09B3F93 for ; Wed, 5 Aug 2015 18:14:32 +0000 (UTC) (envelope-from scott4long@yahoo.com) Received: from nm30.bullet.mail.gq1.yahoo.com (nm30.bullet.mail.gq1.yahoo.com [98.136.217.13]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id E72EA13B7 for ; Wed, 5 Aug 2015 18:14:31 +0000 (UTC) (envelope-from scott4long@yahoo.com) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s2048; t=1438798071; bh=92mH/g3tbkFn3oVsAmGk8sHABBLG1Q0nqejtmBF4MPU=; h=Subject:From:In-Reply-To:Date:Cc:References:To:From:Subject; b=heRnwFASEnh+4KD7AXaT54eznvxBtnWy0PAo6Gxn8PiTlk0fxKNZNbtBz2TktrCjosFU0lopxQhon4pBVbQnpyBw6IVCtzwun/+kFPaAsEmRvimeDDt3ikUL/bye2dRjBC15jHQ0vksuJOYn5uPQY47krUF40Ibmwpo/YOctaoOg3RPXi4mR9tNFD1r8jR8q1LIVTJAZ4zgQCNf1cMFF6g5stqxZREa3lom3YYGatk2X5Y7vPl/K0SuyvTRKoPYUCZyAAseWMhSKyNLE2dHnFi0dNNbB+VxgGUUOQah0djbZE87uw6V6IrXCxkNs2RmjbZvNSEH6jgw3o2chwzl33Q== Received: from [98.137.12.63] by nm30.bullet.mail.gq1.yahoo.com with NNFMP; 05 Aug 2015 18:07:51 -0000 Received: from [208.71.42.209] by tm8.bullet.mail.gq1.yahoo.com with NNFMP; 05 Aug 2015 18:07:51 -0000 Received: from [127.0.0.1] by smtp220.mail.gq1.yahoo.com with NNFMP; 05 Aug 2015 18:07:51 -0000 X-Yahoo-Newman-Id: 688091.12057.bm@smtp220.mail.gq1.yahoo.com X-Yahoo-Newman-Property: ymail-3 X-YMail-OSG: 2jxUPNIVM1kzUxrwL8JmCmFol0UE7XMeQUzHBkkIU3NrdQT BTzOus6mMYmfzecYIGAqk6gDvG3ctXiGu8TGFuKtlQxYO_jKL_KF6uk7C.ZM _fn7geC5zDgJTo7JY4VHJSGLzLR8bzNaQDbKmBr0xTo55aY6JGWWwULhOTnN ET4JprRtlugw61Tdhr6FYWx.T4Hj34Mq44M0NhyE9DP8yKN87r4UozfSqqQN env6iCZthaL9biF2IhXkmJa_8UzN4v6jgDCI6isBd7XDLI6TiZc3NEVqLfQL yqeUhQbUU.HEznQjEt95FD.VQ.JiRXD_LcAFgYUe_dJjFy3wOGyHycbMKuBw 4Yk6kZFi5lJUjTM5JRaGC0Z_GfsLGJtJzU1OcCmr7hfawmDdmR2ezwhveA7S 7Pp2ktGkgrlEbUa1U4Yo4Cs_a4YF5t0VV1rc1zLABz3dysbgwounF16mmP8L 2XPNfXab6xdyHnGHd1CjRf7HaYhmHjH4NtFLm9bLel52fenjtbx8JkB_NU09 IgL.4dyyIOWzGkW.GAOxjqolIV248sIKY5HoLvCRj X-Yahoo-SMTP: clhABp.swBB7fs.LwIJpv3jkWgo2NU8- Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2098\)) Subject: Re: Max queue depth per target device??? From: Scott Long In-Reply-To: Date: Wed, 5 Aug 2015 12:07:49 -0600 Cc: freebsd-scsi@freebsd.org, "Kenneth D. Merry" Content-Transfer-Encoding: quoted-printable Message-Id: <07949D93-5098-49EE-9D1A-95729269716B@yahoo.com> References: To: Sibananda Sahu X-Mailer: Apple Mail (2.2098) X-BeenThere: freebsd-scsi@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: SCSI subsystem List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 05 Aug 2015 18:14:32 -0000 > On Aug 5, 2015, at 11:52 AM, Sibananda Sahu via freebsd-scsi = wrote: >=20 > Hi All, >=20 >=20 >=20 > Is the CAM layer provides per target queue depth setting? >=20 > If yes then can anybody tell me how to implement that in the SIM = driver? >=20 > Or, if no, then is there any proposal to implement per target queue = depth > in FreeBSD CAM layer, similar to that of the Linux SCSI sub-system? >=20 For the SATA transport, CAM takes care of probing the SATA NCQ register = and setting the appropriate queue depth. For the SCSI transport, CAM assumes that the drives will continue to = take commands until they are full, and then will report a QUEUE_FULL = status. When CAM gets that status, it adjusts the queue depth = automatically. So no, there are no plans to set a simple static value like in Linux. = CAM probes for it automatically, so long as the driver passes the QUEUE = FULL status up correctly. Scott