From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934126AbYDQPr7 (ORCPT ); Thu, 17 Apr 2008 11:47:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1762471AbYDQPru (ORCPT ); Thu, 17 Apr 2008 11:47:50 -0400 Received: from webmail1.posta.tim.it ([213.230.128.226]:43541 "EHLO fep08-svc.tim.it" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1761258AbYDQPru (ORCPT ); Thu, 17 Apr 2008 11:47:50 -0400 Message-ID: <48077120.8030007@unimore.it> Date: Thu, 17 Apr 2008 17:47:44 +0200 From: Paolo Valente User-Agent: Thunderbird 2.0.0.12 (Windows/20080213) MIME-Version: 1.0 To: Avi Kivity CC: Jens Axboe , Pavel Machek , linux-kernel@vger.kernel.org Subject: Re: [RESEND][RFC] BFQ I/O Scheduler References: <20080401152903.GB34860@gandalf.sssup.it> <20080416184441.GA3923@ucw.cz> <4806EACB.7040408@unimore.it> <20080417071012.GP12774@kernel.dk> <480709A2.7040606@unimore.it> <20080417083047.GV12774@kernel.dk> <48076A97.9060003@qumranet.com> In-Reply-To: <48076A97.9060003@qumranet.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Avi Kivity ha scritto: > Jumping in at random, does "process" here mean task or mms_struct? If > the former, doesn't that mean that a 100-thread process can starve out > a single-threaded process? > > Perhaps we need hierarchical io scheduling, like cfs has for the cpu. > Hierarchical would simplify isolating groups of threads or processes. However, some simple solution is already available with bfq. For example, if you have to fairly share the disk bandwidth between the above 100 threads and another important thread, you get it by just assigning weight 1 to each of these 100 threads, and weight 100 to the important one. Paolo -- ----------------------------------------------------------- | Paolo Valente | | | Algogroup | | | Dip. Ing. Informazione | tel: +39 059 2056318 | | Via Vignolese 905/b | fax: +39 059 2056199 | | 41100 Modena | | | home: http://algo.ing.unimo.it/people/paolo/ | -----------------------------------------------------------