Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261580AbUDWV4o (ORCPT ); Fri, 23 Apr 2004 17:56:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261597AbUDWV4o (ORCPT ); Fri, 23 Apr 2004 17:56:44 -0400 Received: from spc1-brig1-3-0-cust85.lond.broadband.ntl.com ([80.0.159.85]:32474 "EHLO ppgpenguin.kenmoffat.uklinux.net") by vger.kernel.org with ESMTP id S261580AbUDWV4m convert rfc822-to-8bit (ORCPT ); Fri, 23 Apr 2004 17:56:42 -0400 Date: Fri, 23 Apr 2004 22:56:41 +0100 (BST) From: Ken Moffat To: linux-kernel@vger.kernel.org Subject: IDE throughput in 2.6 - it's good! Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=ISO-8859-15 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1711 Lines: 40 Talk about lies, damned lies, and statistics. I've seen comments about disk throughput, and running hdparm -t is one of my normal tests for new kernels. On this particular box (1000Mhz Duron, 512MB) hdparm regularly reported disk reads of >= 40MB/S, at least on the outside. Then I booted 2.6.5 and the reported speed dropped away to typically 26-28MB/S. I remembered a recent comment about block sizes, so I tested the read speed shown for various partitions. The outer part of the disk has several VFAT partitions, the ext3 partitions on the inside now report around 31MB/S - better than 26, but sounds poor, and 2.6.1 reported a slightly faster speed (might be the compiler, for 2.6.1 I used gcc-2.95.3, now I'm using gcc-3.3.3). All of the 2.6 kernels on this box have preempt enabled. But, when all's said and done these are only numbers. I found the biggest tar on this box (463MiB) and timed - cp from hda10 to hda9 (these are the innermost partitions) sync rm from hda9 sync again Repeated three times, no other users, noted the real time. Under 2.4.25, between 41 and 45 seconds. Under 2.6.1, between 42 and 50 seconds. Under 2.6.5, between 38 and 40 seconds. So, despite the numbers shown by hdparm looking worse, when only one user is doing anything the performance is actually improved. I've no idea which changes have achieved this, but thanks to whoever were involved. Ken -- das eine Mal als Trag?die, das andere Mal als Farce - 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/