From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751402AbWFLGlN (ORCPT ); Mon, 12 Jun 2006 02:41:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751406AbWFLGlN (ORCPT ); Mon, 12 Jun 2006 02:41:13 -0400 Received: from ns.virtualhost.dk ([195.184.98.160]:60470 "EHLO virtualhost.dk") by vger.kernel.org with ESMTP id S1751402AbWFLGlN (ORCPT ); Mon, 12 Jun 2006 02:41:13 -0400 Date: Mon, 12 Jun 2006 08:41:36 +0200 From: Jens Axboe To: Vishal Patil Cc: Linux Kernel Mailing List , Jan Engelhardt Subject: Re: CSCAN vs CFQ I/O scheduler benchmark results Message-ID: <20060612064136.GB4420@suse.de> References: <4745278c0606091230g1cff8514vc6ad154acb62e341@mail.gmail.com> <4745278c0606091915n3ed7563do505664c4f8070f81@mail.gmail.com> <20060611185854.GF13556@suse.de> <4745278c0606111647g7ca1392bjb46936f69d6b668d@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4745278c0606111647g7ca1392bjb46936f69d6b668d@mail.gmail.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org (please don't top post) On Sun, Jun 11 2006, Vishal Patil wrote: > Jan > > I ran the performance benchmark on an IBM machine with the following > harddrive attached to it. > > cat /proc/ide/hda/model > ST340014A Ok, so plain IDE. > Also note the CSCAN implementation is using rbtrees due which the time > complexity of the different operations is O(log(n)) and not O(n) and > that might be the reason that we are getting good values for specially > in case of sequential writes and the random workloads. Extremely unlikely. The sort overhead is completely noise in a test such as yours, an O(n^2) would likely run just as fast. -- Jens Axboe