Re: Linux 2.6.29

Mark Lord
2009-04-03T15:05:29Z

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