From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764784AbXHFWNN (ORCPT ); Mon, 6 Aug 2007 18:13:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759104AbXHFWM7 (ORCPT ); Mon, 6 Aug 2007 18:12:59 -0400 Received: from smtp35.poczta.interia.pl ([80.48.65.35]:41066 "EHLO smtp4.poczta.interia.pl" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751664AbXHFWM6 (ORCPT ); Mon, 6 Aug 2007 18:12:58 -0400 Message-ID: <46B79CDE.2030709@interia.pl> Date: Tue, 07 Aug 2007 00:12:46 +0200 From: =?UTF-8?B?UmFmYcWCIEJpbHNraQ==?= User-Agent: Thunderbird 2.0.0.6 (X11/20070802) MIME-Version: 1.0 To: Dimitrios Apostolou Cc: linux-kernel@vger.kernel.org Subject: Re: high system cpu load during intense disk i/o References: <200708031903.10063.jimis@gmx.net> <200708051903.12414.jimis@gmx.net> <46B60FB7.8030301@interia.pl> <200708052142.14630.jimis@gmx.net> <46B748DE.1060108@interia.pl> <46B773F6.7060603@gmx.net> In-Reply-To: <46B773F6.7060603@gmx.net> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-EMID: cc8d6acc Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > Hello Rafal, Hello, > However I find it quite possible to have reached the throughput limit > because of software (driver) problems. I have done various testing > (mostly "hdparm -tT" with exactly the same PC and disks since about > kernel 2.6.8 (maybe even earlier). I remember with certainty that read > throughput the early days was about 50MB/s for each of the big disks, > and combined with RAID 0 I got ~75MB/s. Those figures have been dropping > gradually with each new kernel release and the situation today, with > 2.6.22, is that hdparm gives maximum throughput 20MB/s for each disk, > and for RAID 0 too! Just tested (plain curiosity). via82cxxx average result @533MHz: /dev/hda: Timing cached reads: 232 MB in 2.00 seconds = 115.93 MB/sec Timing buffered disk reads: 64 MB in 3.12 seconds = 20.54 MB/sec pata_via average result @533MHz: /dev/sda: Timing cached reads: 234 MB in 2.01 seconds = 116.27 MB/sec Timing buffered disk reads: 82 MB in 3.05 seconds = 26.92 MB/sec Same 2.6.23-rc1-git11 kernel. Yes - constant 6MB/s difference (31%). Cool. > Dimitris Regards Rafał ---------------------------------------------------------------------- Jestes sexy? Dodaj swoje fotki i daj sie ocenic na >>>http://link.interia.pl/f1b21