From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261442AbVFQMnZ (ORCPT ); Fri, 17 Jun 2005 08:43:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261656AbVFQMnZ (ORCPT ); Fri, 17 Jun 2005 08:43:25 -0400 Received: from clock-tower.bc.nu ([81.2.110.250]:30340 "EHLO lxorguk.ukuu.org.uk") by vger.kernel.org with ESMTP id S261442AbVFQMnX (ORCPT ); Fri, 17 Jun 2005 08:43:23 -0400 Subject: Re: Odd IDE performance drop 2.4 vs 2.6? From: Alan Cox To: Ondrej Zary Cc: Nick Piggin , Grant Coady , Linux Kernel Mailing List In-Reply-To: <42B07E5D.9070004@rainbow-software.org> References: <42AD6362.1000109@rainbow-software.org> <1118669975.13260.23.camel@localhost.localdomain> <42AD92F2.7080108@yahoo.com.au> <1118675343.13773.1.camel@localhost.localdomain> <42B07E5D.9070004@rainbow-software.org> Content-Type: text/plain Content-Transfer-Encoding: 7bit Message-Id: <1119012053.27908.87.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 (1.4.6-2) Date: Fri, 17 Jun 2005 13:40:56 +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mer, 2005-06-15 at 20:15, Ondrej Zary wrote: > Now I've tested it with preempt disabled and nothing has changed. When > fiddling around with hdparm, I got about 16MB/s max. with 2.6.12-rc5. > With 2.4.31, I got about 21MB/s when just the DMA was enabled > (read-ahead and multcount set to 0 - changing them does not make almost > any difference). multcount is only used for PIO so that would be expected. Similarly the block readahead should matter but not anything drive level. If you compare the hdparm data are both 2.4 and 2.6 selecting the same IDE modes ?