From owner-freebsd-hackers@FreeBSD.ORG Wed Dec 12 13:48:52 2012 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 53B9933B for ; Wed, 12 Dec 2012 13:48:52 +0000 (UTC) (envelope-from se@freebsd.org) Received: from nm15-vm0.bullet.mail.ukl.yahoo.com (nm15-vm0.bullet.mail.ukl.yahoo.com [217.146.183.252]) by mx1.freebsd.org (Postfix) with ESMTP id 9A5988FC12 for ; Wed, 12 Dec 2012 13:48:51 +0000 (UTC) Received: from [217.12.10.82] by nm15.bullet.mail.ukl.yahoo.com with NNFMP; 12 Dec 2012 13:42:50 -0000 Received: from [77.238.184.56] by tm16.bullet.mail.ukl.yahoo.com with NNFMP; 12 Dec 2012 13:42:50 -0000 Received: from [127.0.0.1] by smtp125.mail.ukl.yahoo.com with NNFMP; 12 Dec 2012 13:42:50 -0000 X-Yahoo-Newman-Id: 808341.54573.bm@smtp125.mail.ukl.yahoo.com X-Yahoo-Newman-Property: ymail-3 X-YMail-OSG: g4fy27wVM1lhV4a9mBeNszvsa0p3KOsPyDJbDDsZXHm4t8C 3yRmaItUs3gHKzfVsjey..USsHi6ayjwR3NuEIYVcO1xfK71yv.3VBAj55TK F5gm_vQ05np4bYIGkdxv4.0amzE0Sxwpy0upBbZqADsVPpS7Dsk8pT.rdrcT df.w.aaFWkGW1e5b1w_o_2494lSVbUZmvpSrS52.vqULj_P4UeIg6NQlJ1EP 7DvfMbJb9Q1Mqcds.OX8KMfDEMpUYs.xt1a5g6WlAZUn_2d0jLEMsypeoLrS TCpd915U8Dm4YOhdtfMqgLBCBEgDrE4hBVThubf4hEnVFLecA9Jt5tlJbD_v iZTucOP9gs2nhzzWIrKNcGLW8E0kRdn_VlPyx35m9N752mTKpdR37RmLs.TY 1tNUs9COLbmVzqpOWGo5UnwzD0nUUUryFUMh_6XOq3EdC X-Yahoo-SMTP: iDf2N9.swBDAhYEh7VHfpgq0lnq. Received: from [192.168.119.18] (se@87.158.11.102 with plain) by smtp125.mail.ukl.yahoo.com with SMTP; 12 Dec 2012 13:42:50 +0000 GMT Message-ID: <50C889D3.1050404@freebsd.org> Date: Wed, 12 Dec 2012 14:42:43 +0100 From: Stefan Esser User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 CC: freebsd-hackers@freebsd.org Subject: Re: FreeBSD for serious performance? References: <20121211204323.310760@gmx.com> In-Reply-To: X-Enigmail-Version: 1.4.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 12 Dec 2012 13:48:52 -0000 Am 11.12.2012 22:40, schrieb Adrian Chadd: > .... I'm not seeing: > > * any references to driver code that exhibits that very broken behaviour; > * any patches from you to implement NCQ on your nforce chipset; > * any offer of incentive to any developer to add that support. > > Now, (1) is definitely worrying but as you've not provided any actual > information, the level of helpfulness of this comment is 0. > (2) and (3) would go a long way to making FreeBSD "better". Yes, but the answer to (1) seems to be very simple: The cause of the low write performance is the disabled write cache. Enabling the write cache is unsafe on SATA drives (with or without NCQ), since they do not make any guarantees that nearby data is not lost if power fails during a disk write. It never happened to me, but there is a reason that SAS drives have less capacity, much lower BER (one to two magnitudes) and are more expensive than SATA drives. The solution to the performance problem is simple: Turn on the write cache. If the data is valuable, then SAS is the solution to both the performance and the inherent reliability problems. If SATA with NCQ really provides acceptable reliability, then a cheap SATA controller with NCQ support in FreeBSD might also be an option, at a cost that would pay one developer hour. Asking Nvidia to release the confidential documentation for their chip-set might help, but I doubt that there is much interest to add support for NCQ to an obsolete chip-set, today, unless you pay a developer (and even then ...). If all these don't work for you, then you may really be better served by Linux with the drivers donated by Nvidia. And if you buy a new system, you may consider choosing components from vendors that do not provide binary blobs for selected operating systems, but publish the necessary documentation for driver writers (or which develop open source drivers for FreeBSD, not only for Linux). There are so many ways to solve your problem