Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263179AbTKART4 (ORCPT ); Sat, 1 Nov 2003 12:19:56 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263275AbTKART4 (ORCPT ); Sat, 1 Nov 2003 12:19:56 -0500 Received: from h234n2fls24o1061.bredband.comhem.se ([217.208.132.234]:60647 "EHLO oden.fish.net") by vger.kernel.org with ESMTP id S263179AbTKARTy (ORCPT ); Sat, 1 Nov 2003 12:19:54 -0500 Date: Sat, 1 Nov 2003 18:22:16 +0100 From: Voluspa To: linux-kernel@vger.kernel.org Subject: Re: READAHEAD Message-Id: <20031101182216.3e642eda.lista2@comhem.se> Organization: The Foggy One X-Mailer: Sylpheed version 0.8.10 (GTK+ 1.2.10; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1440 Lines: 58 On 2003-11-01 9:15:28 Age Huisman wrote: >Andrew Morton wrote: >> Andrew Morton wrote: >> >>>Please, just use time, cat, dd, etc. >>> >>> mount /dev/xxx /mnt/yyy >>> dd if=/dev/zero of=/mnt/yyy/x bs=1M count=1024 >>> umount /dev/xxx >>> mount /dev/xxx /mnt/yyy >>> time cat /mnt/yyy/x > /dev/null [...] >Here are the new test results. [...] >I think you were right :-) I see an improvement with 512 instead of the default 256, but no further speedups with 1024 or 2048 - no point in trying 4096: readahead = 256 (on) real 0m39.494s user 0m0.346s sys 0m5.436s Timing buffered disk reads: 64 MB in 2.80 seconds = 22.84 MB/sec readahead = 512 (on) real 0m34.418s user 0m0.302s sys 0m5.304s Timing buffered disk reads: 64 MB in 2.16 seconds = 29.63 MB/sec And for the nostalgic people out there, here's what "hdparm /dev/hdX" has in its readahead slot under 2.5.X: 2.5.5-pre1 readahead = 8 (on) 2.5.5-pre1-final (AKA 2.5.5) to 2.5.8-pre2 BLKRAGET failed: Input/output error 2.5.8-pre3 to 2.5.9 don't compile. 2.5.10 readahead = 0 (off) 2.5.11 failed to boot and damaged the filesystem. 2.5.12 and onwards readahead = 256 (on) Mvh Mats Johannesson - 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/