[mythtv] high cpu load for xorg with 50fps playback

[Markus Schulz]

Hello,

i've written a full-framerate patch for mythtv and have integrated the 
adaptive dscaler greedy high motion deinterlacer (taken from xine-lib).

In general it runs nice and perfectly smooth for all interlaced 
material. 
But i have an ugly problem, if i'm run the patched myth on a 50Hz 
display (DFP-beamer) xorg sometimes (rather often) consumes much cpu 
power (max load on a single core). Running on my CRT with 75Hz or 100Hz 
there is no problem. 
Looks like a problem when running with FPS == Refresh Rate.

I've taken some strace logs from xorg, in error case there were 35000 
calls per second to gettimeofday from xorg?!? Normally the rate is much 
much lower.

Anyone has an idea whats the reason for this high rate of gettimeofday 
calls? The cpu time goes to xorg instead of mythtfrontend, therefore 
should it has to do with xv-calls? What can i do further to analyse 
this problem?

-- 
Markus Schulz