For the past few weeks I’ve been puzzled by the significant load shown on my MythTV backend generated by the kdvb-fe-0 process. The server was running at 50% load or higher even when there was nothing being recorded.
I poked around and found that the kdvb-fe-0 process is created by the Linux DVB drivers, which is the driver used for my TV capture card. Because this driver is running so close to the kernel I am not quite sure how to troubleshoot it. The software tools I would normally use may not work at this level.
Fortunately for me, I seem to have inadvertently discovered the cause of the load. When Kelly complained today that a few recent programs did not record properly I decided to take this up again. She found that our HDTV was getting a poor signal as well, which indicated the problem wasn’t confined to my MythTV backend. I set the signal meter on for my HDTV, handed Kelly a walkie-talkie, and headed to the attic to tweak the antenna.
It turns out my antenna connector is faulty! With just a slight adjustment the signal goes from 10 to 94 (on a scale from 1 to 100). I jiggled the connector a bit while Kelly read the signal readings to me and found a spot where the signal came in reliably.
Annnnnd …. like magic the load on my MythTV backend completely disappeared! The faulty antenna connection was somehow placing a phantom load on my capture card (and my MythTV system) even though it was supposed to be idle! I never would’ve thought that a bad connection would have that kind of effect on my capture card.
So if anyone else happens to see a mystery load on their MythTV systems in the kdvb-fe process, you might want to check your cables.