After upgrading to Ubuntu 8.10, I started having performance problems with video playback on MythFrontEnd. I have a video encoder on my TV Tuner card, and I frequently record 2 show simultaneously, always with < 10% CPU utlization, so I knew
mythbackend wasn't the problem.
The symptoms I saw were:
topshows high CPU usage in
mythfrontend, but it also indicates other programs running with high CPU use, which is unusual.
So I started an experiment: each night I altered my MythTV settings and observing the running system. the next day My family reported what they saw and I changed more settings. I tried the following things:
xfs_fsr(I'm using XFS on LVM…perfect for mythTV's large files).
mythbackend, and the computer
It wasn't until I got to the last step–killing running processes–that I found a solution. I kept seeing
gnome-screensaver in the list of running processes, but it wasn't consuming a lot of CPU time. But that's when it hit me….screensavers kick in after a period of keyboard and mouse inactivity, which could explain why the symptoms start several minutes after the beginning of a TV program. And my efforts to catch the problem by suddenly bringing a process monitor into the foreground with <alt>-<tab> could be thwarted because of how screensavers react to keystrokes. So I decided to kill the screensaver…
and the problem went away. But it returned the next day. I found that the screensaver had been restarted. So I went into the screensaver settings in Gnome and deselected the “Screensaver” checkbox. That solved the problem too, and it didn't return.
Late in the problem solving process, I found a particular google search (this query) that revealed plenty of issues between MythTV and
gnome-screensaver. Why is it that I find the answers after I solve the problem?