From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 12 Dec 2001 18:50:29 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 12 Dec 2001 18:50:21 -0500 Received: from penguin.e-mind.com ([195.223.140.120]:52040 "EHLO penguin.e-mind.com") by vger.kernel.org with ESMTP id ; Wed, 12 Dec 2001 18:50:10 -0500 Date: Thu, 13 Dec 2001 00:49:33 +0100 From: Andrea Arcangeli To: "H . J . Lu" Cc: linux kernel Subject: Re: Slow Disk I/O with QPS M3 80GB HD Message-ID: <20011213004933.T4801@athlon.random> In-Reply-To: <20011210203452.A3250@lucon.org> <20011210235708.A17743@lucon.org> <20011211154331.A32433@lucon.org> <20011212092954.N4801@athlon.random> <20011212153806.A22202@lucon.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.3.12i In-Reply-To: <20011212153806.A22202@lucon.org>; from hjl@lucon.org on Wed, Dec 12, 2001 at 03:38:06PM -0800 X-GnuPG-Key-URL: http://e-mind.com/~andrea/aa.gnupg.asc X-PGP-Key-URL: http://e-mind.com/~andrea/aa.asc Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 12, 2001 at 03:38:06PM -0800, H . J . Lu wrote: > H.J. > ---- > 3 files on USB: > > # ls -l > total 5984 > -rwxr-xr-x 1 root root 1991481 Dec 8 21:44 dsc00002.jpg > -rwxr-xr-x 1 root root 2432127 Dec 8 23:54 dsc00005.jpg > -rwxr-xr-x 1 root root 1675563 Dec 8 23:59 dsc00009.jpg > > 1. 2.4.10-pre10 > > # time /bin/cp * /tmp/ > real 0m0.623s > user 0m0.000s > sys 0m0.100s > > 2. 2.4.10-pre10aa1 > > # time /bin/cp * /tmp/ > real 0m8.952s > user 0m0.000s > sys 0m0.190s > > > 3. 2.4.10-pre11 > > # time /bin/cp * /tmp/ > real 0m8.851s > user 0m0.000s > sys 0m0.170s but the above have nothing to do with the blkdev-pagecache. Blkdev-pagecache can matter only with blkdev accesses, blkdev-pagecache cannot make any difference if the I/O passes through any fs (not via the block_dev layer) like in the above case. Can you try to take those cp under strace timestamp and see what's the syscall that blocks? Andrea