From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264283AbTDPKCf (for ); Wed, 16 Apr 2003 06:02:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264284AbTDPKCf (for ); Wed, 16 Apr 2003 06:02:35 -0400 Received: from c-97a870d5.037-69-73746f23.cust.bredbandsbolaget.se ([213.112.168.151]:29066 "EHLO zaphod.guide") by vger.kernel.org with ESMTP id S264283AbTDPKCd (for ); Wed, 16 Apr 2003 06:02:33 -0400 To: Andrew Morton Cc: Chuck Ebbert <76306.1226@compuserve.com>, linux-kernel@vger.kernel.org, alan@lxorguk.ukuu.org.uk Subject: Re: DMA transfers in 2.5.67 References: <200304160548_MC3-1-349F-E844@compuserve.com> <20030416031144.613b0cc7.akpm@digeo.com> From: mru@users.sourceforge.net (=?iso-8859-1?q?M=E5ns_Rullg=E5rd?=) Date: 16 Apr 2003 12:13:09 +0200 In-Reply-To: <20030416031144.613b0cc7.akpm@digeo.com> Message-ID: User-Agent: Gnus/5.0808 (Gnus v5.8.8) XEmacs/21.4 (Portable Code) MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andrew Morton writes: > > # mount /ext3_fs > > # time dd if=/ext3_fs/100MiB_file of=/dev/null bs=32k > > > > 2.4.20aa1 : 3.3 sec (exactly what I expect to see) > > 2.5.66 : 6.6 sec > > With this test 2.4 will leave a lot more unwritten dirty data in memory. > > You should include a `sync' in the timings. That was reading a file discarding that data. A sync shouldn't make any difference. -- Måns Rullgård mru@users.sf.net