[mythtv-commits] Ticket #2765: High CPU usage in mythbackend

[MythTV]

#2765: High CPU usage in mythbackend
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 Reporter:  mythtv at salfter.dyndns.org  |       Owner:  ijr    
     Type:  defect                     |      Status:  new    
 Priority:  major                      |   Milestone:  unknown
Component:  mythtv                     |     Version:  0.20   
 Severity:  medium                     |  
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 While watching some recently-recorded shows, I found that they hadn't been
 commflagged.  When I checked, the job queue had several commflagging jobs
 piled up.  One of them (last night's episode (recorded in HD, if it
 matters) of Las Vegas) had been running since some time yesterday, but it
 wasn't using much CPU.  I killed it and let it move on to the next job.

 A short time later, I noticed that mythbackend was running with an
 abnormally high load.  It's just recording from a PVR-350 as I write this,
 but it's taking 93-95% of the processor's time as I write this.  The
 current load average (with mythbackend, mythcommflag, and Firefox being
 the main running processes) is hovering around 3.9-4.0.  My Mythbox is an
 Athlon 64 3700 with 2 GB of RAM, so the swap has barely been touched since
 startup.

 Relevant version numbers (everything was built from Gentoo ebuilds):

  * mythtv-0.20_p11626
  * ivtv-0.8.1
  * libdvb-0.5.5.1-r2
  * gentoo-sources-2.6.18-r3 (this is the kernel)
  * nvidia-drivers-1.0.9629 (but this shouldn't affect a backend problem)

 The recording devices are a PVR350 and an A180.

 Now that the last recording is complete, the usage by mythbackend has gone
 to nearly 100% and the mythcommflag job that should be running is at 0%.
 After restarting mythbackend, mythcommflag is finally able to get some
 "quality time" with the processor.  Load average is now down below 1.0,
 even with a couple of commflag jobs running simultaneously.

 The only info in the system log pertaining to MythTV is a couple of
 mythfilldatabase segfaults, but that would be a separate problem.

-- 
Ticket URL: <http://svn.mythtv.org/trac/ticket/2765>
MythTV <http://www.mythtv.org/>
MythTV