From owner-freebsd-current@FreeBSD.ORG Wed Sep 2 15:25:32 2009 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 5141F1065672; Wed, 2 Sep 2009 15:25:32 +0000 (UTC) (envelope-from 482254ac@razorfever.net) Received: from ironport2-out.teksavvy.com (ironport2-out.teksavvy.com [206.248.154.182]) by mx1.freebsd.org (Postfix) with ESMTP id 01BBE8FC16; Wed, 2 Sep 2009 15:25:31 +0000 (UTC) X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: ArUEAN8rnkpMCrCL/2dsb2JhbACBUxraMYJrgTAFgVeGGQ X-IronPort-AV: E=Sophos;i="4.44,318,1249272000"; d="scan'208";a="44994399" Received: from 76-10-176-139.dsl.teksavvy.com (HELO server.razorfever.net) ([76.10.176.139]) by ironport2-out.teksavvy.com with ESMTP; 02 Sep 2009 11:24:17 -0400 Received: from [192.168.0.197] ([192.168.0.197]) by server.razorfever.net (8.13.8/8.13.8) with ESMTP id n82FPAMF017373; Wed, 2 Sep 2009 11:25:10 -0400 (EDT) (envelope-from 482254ac@razorfever.net) Message-ID: <4A9E8E82.9050708@razorfever.net> Date: Wed, 02 Sep 2009 11:25:54 -0400 From: "Derek (freebsd lists)" <482254ac@razorfever.net> User-Agent: Thunderbird 2.0.0.23 (X11/20090817) MIME-Version: 1.0 To: Alexander Motin References: <4A9E8677.1020208@FreeBSD.org> In-Reply-To: <4A9E8677.1020208@FreeBSD.org> Content-Type: text/plain; charset=KOI8-R; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: clamav-milter 0.95.2 at server.razorfever.net X-Virus-Status: Clean Cc: FreeBSD-Current Subject: Re: siis/atacam/ata/gmirror 8.0-BETA3 disk performance X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 02 Sep 2009 15:25:32 -0000 Thank you for your informative response. Alexander Motin wrote: > Derek (freebsd lists) wrote: >> I've been testing the new siis driver, and I have found no >> appreciable performance change, using dd as a measure of "raw" >> performance. > > On linear read/write, without port multipliers used, performance of siis > driver is not so much differs from legacy driver. The most of it's > benefits are NCQ, FIS-based switching and command queuing affect mostly > highly parallel random workload. > That's good news, in that the behaviour is expected. >> I get about 40MB/s read, and 30MB/s write. See attached >> bench-*.txt files. > > It's too small, indeed. Actually, there are two different kinds of siis > compatible devices: SiI3124 and SiI3132/SiI3531. SiI3124 is more > expensive PCI-X card, sometimes it goes with built-in PCIe x4 bridge. To > operate effectively it needs effective bus. Inserting it to usual PCI or > PCIe x1 slot kills any hope. SiI3132/SiI3531 same time are cheap PCIe x1 > cards. Nobody have ever seen them giving more 130-150MB/s, even looking > that PCIe x1 should give 2.5Gb/s. > I've got the SiI3124, plugged into a PCI bus. While I know PCI is really slow by today's standards, I was hoping to see performance closer to the bus limits. My rates are 30% of the maximum "theoretical" bus utilization (33Mhz*32-bits). The figures you give for PCIe x1 are around 40% of maximum (on the low end of the figures) utilization, so we're in the same neighbourhood. > To completely load gmirror on read operations, you may need to run two > dd's same time. Also make sure, that your gmirror runs in round-robin > mode. Default split mode, which should help with linear read, is IMHO > ineffective, at least with default MAXPHYS and slice values. > ... I'll play around with this as well, I'm not too interested in tweaking stuff much in production, but it would be interesting to see just how this performs. In production, I plan to use the gmirror for swap, and zfs for everything else. It seems that for swap usage, linear read isn't a great model. Thanks again! - Derek