Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935757AbZDCT6g (ORCPT ); Fri, 3 Apr 2009 15:58:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755166AbZDCT61 (ORCPT ); Fri, 3 Apr 2009 15:58:27 -0400 Received: from srv5.dvmed.net ([207.36.208.214]:43572 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754469AbZDCT6Z (ORCPT ); Fri, 3 Apr 2009 15:58:25 -0400 Message-ID: <49D66A40.5020503@garzik.org> Date: Fri, 03 Apr 2009 15:57:52 -0400 From: Jeff Garzik User-Agent: Thunderbird 2.0.0.21 (X11/20090320) MIME-Version: 1.0 To: Mark Lord CC: Lennart Sorensen , 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> <49D625A0.1030202@rtr.ca> In-Reply-To: <49D625A0.1030202@rtr.ca> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Score: -4.4 (----) X-Spam-Report: SpamAssassin version 3.2.5 on srv5.dvmed.net summary: Content analysis details: (-4.4 points, 5.0 required) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1782 Lines: 51 Mark Lord wrote: > 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. mythtv/libs/libmythtv/ThreadedFileWriter.cpp is a good place to start (Sync method... uses fdatasync if available, fsync if not). mythtv is definitely a candidate for sync_file_range() style output, IMO. Jeff -- 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/