From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765559AbYDQK3i (ORCPT ); Thu, 17 Apr 2008 06:29:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754529AbYDQK33 (ORCPT ); Thu, 17 Apr 2008 06:29:29 -0400 Received: from tone.orchestra.cse.unsw.EDU.AU ([129.94.242.59]:32969 "EHLO tone.orchestra.cse.unsw.EDU.AU" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752407AbYDQK32 (ORCPT ); Thu, 17 Apr 2008 06:29:28 -0400 From: Aaron Carroll To: Paolo Valente Date: Thu, 17 Apr 2008 20:24:09 +1000 Message-ID: <48072549.7040104@cse.unsw.edu.au> User-Agent: Thunderbird 2.0.0.12 (X11/20080316) MIME-Version: 1.0 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> In-Reply-To: <480709A2.7040606@unimore.it> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Paolo Valente wrote: > In my opinion, the time-slice approach of cfq is definitely better > suited than the (sector) budget approach for this type of workloads. On > the opposite end, the price of time-slices is unfairness towards, e.g., > threads doing sequential accesses. In bfq we were mainly thinking about How do you figure that? This is a situation where time-slices work nicely, because they implicitly account for the performance penalty of poor access patterns. The sequential-accessing processes (and the system overall) ends up with higher throughput. -- Aaron