[mythtv] fix for IOBOUND - blocking in ThreadedFileWriter::Write

[Torbjörn Jansson]

mythtv-dev-bounces at mythtv.org <> wrote:
> Hi,
> 
> I'm running myth 0.18 release version on a 2.6.12.1 kernel. My card is
> HD3000 HDTV tuner card. I've one 180GB hard drive in my setup,
> standard knoppix myth partition. /, /root, /cache and /myth , are all
> ext 3. 
> 
> Whenever the tuner is recording a program, and I try to copy a large
> file, I get the following error message in the backend logs.
> 
> 2005-07-06 16:07:00.217 IOBOUND - blocking in
> ThreadedFileWriter::Write()
> 2005-07-06 16:07:05.419 IOBOUND - blocking in
> ThreadedFileWriter::Write()
> 2005-07-06 16:07:09.360 IOBOUND - blocking in
> ThreadedFileWriter::Write()
> 2005-07-06 16:07:17.400 IOBOUND - blocking in
> ThreadedFileWriter::Write()
> 2005-07-06 16:07:26.623 IOBOUND - blocking in
> ThreadedFileWriter::Write()
> 2005-07-06 16:07:31.437 IOBOUND - blocking in
> ThreadedFileWriter::Write()
> 
> If I stop the copy, the message will also stop.
> 

One thing you may want to try is to change the io scheduler to cfq (
elevator=cfq argument to kernel at boot )
That should allow each program to get equal access to the disk so one one is
starved

I think cfq is the default for fedora.

These 2 links may be of intrest:
http://lwn.net/Articles/22429/
http://www.redhat.com/magazine/008jun05/features/schedulers/