[mythtv-users] Mythbackend taking 50% CPU w/PVR150 or 250 when recording

[Stuart Larson]

Hi all,
  First off, system info:  Myth from 0.19-fixes branch, checked out from
2/24/06.  Running the backend on FC4, IVTV 4.2, and two PVR cards - one
is a 150, the other a 250.  My storage dir is on a 4-disk LVM, formatted
in ReiserFS.  PC is an AMD Sempron 3100, with 1GB of ram.  DMA is
enabled on all disks.
   I've had no problems with recording up until this weekend.  What I
started seeing is when mythbackend is recording, it starts taking up
around 50% CPU.  Normally I wouldn't think this would affect playback
on the local frontend (they are on the same machine), but if either of
the cards were recording, I'd start seeing skips and pauses,
corresponding to mythbackend's CPU usage.  The actual recordings, onced
finished, play back fine, it just appears that playback of other media
(the entire box was slow) suffered because of mythbackend taking up so
much CPU.  Before this, the highest I saw mythbackend take was around
10%.  If it's relevant, I'm recording at 480x480, around 3500 bitrate,
and I have 1 GB reserved for files.
  What I noticed (and from searching the lists, it looks like this was an
issue brought up but not really resolved), was that this started
happening when my storage space went under 10G available.  Once I
cleaned up some old recordings and got more space available, mythbackend
went back to using 3-10% CPU when recording...  I did check the
mythbackend log, and I did not see anything out of the ordinary - no
messages about expiring old programs.  I ran it on --verbose all (whoah
lots of info!) and also did not see anything out of the ordinary.
  Has anyone seen this issue before?  I was able to resolve this just by
cleaning out old recordings, but I wonder if there's a setting I'm
overlooking that would cause/fix this type of behavior.

Thanks for any help,
Stuart