Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030209AbWJQBYi (ORCPT ); Mon, 16 Oct 2006 21:24:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030212AbWJQBYh (ORCPT ); Mon, 16 Oct 2006 21:24:37 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:20939 "EHLO pentafluge.infradead.org") by vger.kernel.org with ESMTP id S1030209AbWJQBYg (ORCPT ); Mon, 16 Oct 2006 21:24:36 -0400 Subject: Re: Bandwidth Allocations under CFQ I/O Scheduler From: Arjan van de Ven To: "Phetteplace, Thad (GE Healthcare, consultant)" Cc: linux-kernel@vger.kernel.org In-Reply-To: References: Content-Type: text/plain Organization: Intel International BV Date: Tue, 17 Oct 2006 03:24:29 +0200 Message-Id: <1161048269.3245.26.camel@laptopd505.fenrus.org> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 (2.2.3-2.fc4) Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1343 Lines: 31 On Mon, 2006-10-16 at 16:46 -0400, Phetteplace, Thad (GE Healthcare, consultant) wrote: > The I/O priority levels available under the CFQ scheduler are > nice (no pun in intended), but I remember some talk back when > they first went in that future versions might include bandwidth > allocations in addition to the 'niceness' style. Is anyone out > there working on that? If not, I'm willing to hack up a proof > of concept... I just wan't to make sure I'm not reinventing > the wheel. Hi, it's a nice idea in theory. However... since IO bandwidth for seeks is about 1% to 3% of that of sequential IO (on disks at least), which bandwidth do you want to allocate? "worst case" you need to use the all-seeks bandwidth, but that's so far away from "best case" that it may well not be relevant in practice. Yet there are real world cases where for a period of time you approach worst case behavior ;( Greetings, Arjan van de Ven -- if you want to mail me at work (you don't), use arjan (at) linux.intel.com Test the interaction between Linux and your BIOS via http://www.linuxfirmwarekit.org - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/