From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261760AbULBUaC (ORCPT ); Thu, 2 Dec 2004 15:30:02 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261757AbULBUaB (ORCPT ); Thu, 2 Dec 2004 15:30:01 -0500 Received: from fw.osdl.org ([65.172.181.6]:29846 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S261753AbULBU3w (ORCPT ); Thu, 2 Dec 2004 15:29:52 -0500 Date: Thu, 2 Dec 2004 12:34:07 -0800 From: Andrew Morton To: Jens Axboe Cc: linux-kernel@vger.kernel.org, nickpiggin@yahoo.com.au Subject: Re: Time sliced CFQ io scheduler Message-Id: <20041202123407.5f8ba355.akpm@osdl.org> In-Reply-To: <20041202201904.GD26695@suse.de> References: <20041202130457.GC10458@suse.de> <20041202134801.GE10458@suse.de> <20041202114836.6b2e8d3f.akpm@osdl.org> <20041202195232.GA26695@suse.de> <20041202121938.12a9e5e0.akpm@osdl.org> <20041202201904.GD26695@suse.de> X-Mailer: Sylpheed version 0.9.7 (GTK+ 1.2.10; i586-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 Jens Axboe wrote: > > > So what are you doing different? > > Doing sync io, most likely. My results above are 64k O_DIRECT reads and > writes, see the mention of the test cases in the first mail. OK. Writer: while true do write-and-fsync -o -m 100 -c 65536 foo done Reader: time-read -o -b 65536 -n 256 x (This is O_DIRECT) or: time-read -b 65536 -n 256 x (This is buffered) `vmstat 1': procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 1 1 1032 137412 4276 84388 32 0 15456 25344 1659 1538 0 3 50 47 0 1 1032 137468 4276 84388 0 0 0 32128 1521 1027 0 2 51 48 0 1 1032 137476 4276 84388 0 0 0 32064 1519 1026 0 1 50 49 0 1 1032 137476 4276 84388 0 0 0 33920 1556 1102 0 2 50 49 0 1 1032 137476 4276 84388 0 0 0 33088 1541 1074 0 1 50 49 0 2 1032 135676 4284 85944 0 0 1656 29732 1868 2506 0 3 49 47 1 1 1032 96532 4292 125172 0 0 39220 128 10813 39313 0 31 35 34 0 2 1032 57724 4332 163892 0 0 38828 128 10716 38907 0 28 38 35 0 2 1032 18860 4368 202684 0 0 38768 128 10701 38845 1 28 38 35 0 2 1032 3672 4248 217764 0 0 39188 128 10803 39327 0 28 37 34 0 1 1032 2832 4260 218840 0 0 16812 17932 5504 17457 0 14 46 40 0 1 1032 2832 4260 218840 0 0 0 30876 1501 974 0 1 50 49 0 1 1032 2944 4260 218840 0 0 0 33472 1537 1068 0 2 50 48 0 1 1032 2944 4260 218840 0 0 0 33216 1533 1046 0 2 50 48 Ugly. (write-and-fsync and time-read are from http://www.zip.com.au/~akpm/linux/patches/stuff/ext3-tools.tar.gz)