From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932902AbZDCPF3 (ORCPT ); Fri, 3 Apr 2009 11:05:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1764822AbZDCPFJ (ORCPT ); Fri, 3 Apr 2009 11:05:09 -0400 Received: from rtr.ca ([76.10.145.34]:35584 "EHLO mail.rtr.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1763546AbZDCPFI (ORCPT ); Fri, 3 Apr 2009 11:05:08 -0400 Message-ID: <49D625A0.1030202@rtr.ca> Date: Fri, 03 Apr 2009 11:05:04 -0400 From: Mark Lord Organization: Real-Time Remedies Inc. User-Agent: Thunderbird 2.0.0.21 (X11/20090318) MIME-Version: 1.0 To: Lennart Sorensen Cc: Jens Axboe , Linus Torvalds , Ingo Molnar , Andrew Morton , tytso@mit.edu, drees76@gmail.com, jesper@krogh.cc, Linux Kernel Mailing List Subject: Re: Linux 2.6.29 References: <20090326174704.cd36bf7b.akpm@linux-foundation.org> <20090326182519.d576d703.akpm@linux-foundation.org> <20090401210337.GB3797@csclub.uwaterloo.ca> <20090401143622.b1885643.akpm@linux-foundation.org> <20090402010044.GA16092@elte.hu> <20090403040649.GF3795@csclub.uwaterloo.ca> <20090403072507.GO5178@kernel.dk> <20090403142129.GH3795@csclub.uwaterloo.ca> In-Reply-To: <20090403142129.GH3795@csclub.uwaterloo.ca> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Lennart Sorensen wrote: > > Well the system is setup like this: > > Core 2 Quad Q6600 CPU (2.4GHz quad core). > Asus P5K mainboard (Intel P35 chipset) > 6GB of ram > PVR500 dual NTSC tuner pci card .. > So the behaviour with cfq is: > Disk light seems to be constantly on if there is any disk activity. iotop > can show a total io of maybe 1MB/s and the disk light is on constantly. .. Lennart, I wonder if the problem with your system is really a Myth/driver issue? Curiously, I have a HVR-1600 card here, and when recording analog TV with it the disk lights are on constantly. The problem with it turns out to be mythbackend doing fsync() calls ten times a second. My other tuner cards don't have this problem. So perhaps the PVR-500 triggers the same buggy behaviour as the HVR-1600? To work around it here, I decided to use a preload library that replaces the frequent fsync() calls with a more moderated behaviour: http://rtr.ca/hvr1600/libfsync.tar.gz Grab that file and try it out. Instructions are included within. Report back again and let us know if it makes any difference. Someday I may try and chase down the exact bug that causes mythbackend to go fsyncing berserk like that, but for now this workaround is fine. Cheers