From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933435AbXHFXt1 (ORCPT ); Mon, 6 Aug 2007 19:49:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933137AbXHFXtQ (ORCPT ); Mon, 6 Aug 2007 19:49:16 -0400 Received: from mail.gmx.net ([213.165.64.20]:52296 "HELO mail.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S932623AbXHFXtP (ORCPT ); Mon, 6 Aug 2007 19:49:15 -0400 X-Authenticated: #4463548 X-Provags-ID: V01U2FsdGVkX1/H9M5XbOjHsBovJbuYALfSWcmabugXxVmg04ecqG 6A3wB8Ar/Mzr5O Message-ID: <46B7C18E.1050008@gmx.net> Date: Tue, 07 Aug 2007 02:49:18 +0200 From: Dimitrios Apostolou User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.0.10) Gecko/20070301 SeaMonkey/1.0.8 MIME-Version: 1.0 To: =?UTF-8?B?UmFmYcWCIEJpbHNraQ==?= 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> <46B79CDE.2030709@interia.pl> In-Reply-To: <46B79CDE.2030709@interia.pl> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Y-GMX-Trusted: 0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Rafał Bilski wrote: >> 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 Interesting! I haven't tried libata myself on that system, I only have remote access to it so I'm a bit afraid... Rafal, I hope that system you run hdparm on isn't the archlinux one! Is it easy to load an old kernel (even two years old) and do the same test? If it is, please let me know of the results. Thanks in advance, Dimitris