High CPU with OpenGL video playback
For a long time I've had a case where CPU usage cycles between low and 100% when using OpenGL rendering in apps like xing, gxine, mplayer, mythtv, etc.., only when OpenGL vsync is enabled.
When the CPU usage is 100%, the video plays good and there is no tearing. When the CPU use randomly cycles down, the video continues to play ok but there is a tear line that appears. A short time later the CPU use will go back to 100% and the tear line disappears again. This "CPU cycling" just continues forever, visual playback of video is unaffected other than the tear line that appears when CPU use cycles down.
Anyone see this before? Is it fixed with a driver >180.53? When OpenGL vsync is turned off, or set to the other monitor from which the video is playing, there is no high CPU usage, but there is tearing.
This happens to me with 2 different video cards and drivers:
7600GS with 173.xx and 177.xx drivers.
9500GT with 180.53 driver
Environment is Ubuntu 9.04 32 bit, Gnome 2.26, Metacity
Twinview spanning enabled, DFP and TV (I use environment variables to change which monitor to sync to)
Composite disabled in xorg
UseEvents and TripleBuffering enabled in xorg
nvidia-settings shows only one "performance level" and it's always set to maximum