Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 17 Jun 2002 20:15:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 17 Jun 2002 20:15:14 -0400 Received: from twinlark.arctic.org ([208.44.199.239]:44230 "EHLO twinlark.arctic.org") by vger.kernel.org with ESMTP id ; Mon, 17 Jun 2002 20:15:12 -0400 Date: Mon, 17 Jun 2002 17:15:13 -0700 (PDT) From: dean gaudet To: Andrew Morton cc: linux-kernel@vger.kernel.org Subject: Re: 3x slower file reading oddity In-Reply-To: <3D0E7041.860710CA@zip.com.au> Message-ID: X-comment: visit http://arctic.org/~dean/legal for information regarding copyright and disclaimer. MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 996 Lines: 30 On Mon, 17 Jun 2002, Andrew Morton wrote: > I rather depends on what is in /tmp/filelist. I assume it's > something like the output of `find'. And I assume you're > using ext2 or ext3? yup: find mail1 mail2 -type f -print0 >/tmp/filelist ext3. thanks for the description of the block groups... that all makes more sense now. > You'll get best throughput with a single read thread. what if you have a disk array with lots of spindles? it seems at some point that you need to give the array or some lower level driver a lot of i/os to choose from so that it can get better parallelism out of the hardware. i see similar slowdowns on a 4-IDE-disk softRAID5+LVM+ext3 setup (SMP 2.4.19-pre7-ac4). not nearly as bad as on the single disk. -dean - 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/