[mythtv-users] HD, XvMC, and realtime

[Gary Dezern]

Running 19-fixes (current as of this afternoon) and mythfrontend has 
perms to set itself as realtime. I'm running on an Athlon64 3800 X2 on 
linux kernel 2.6.16, with an FX 5200 AGP 8x.

Watching HD playback right now, and also have 'top' running in an ssh.  
'top' is set to show threads.  Nothing else is currently running on the 
machine.  FE is spitting out prebuffering pause messages like crazy (as 
it often does while I'm watching HD.)

There are two "mythfrontend" threads sitting near the top of the 'top' 
list, as well as one 'X' thread.  In a given moment, one FE thread uses 
about 50% of one CPU.  X uses about 5% of one CPU.  The second FE thread 
rarely uses more than 1% of any CPU. 

Now, here's the odd thing:  The FE thread thats barely using any CPU at 
all is marked as SCHED_FIFO, nice -19.  In other words, the _only_ 
thread I can see which myth has flagged as realtime is barely doing 
anything at all.

(Is this the right list for this, or should I be posting this elsewhere?)

I'm going to mess around with this some more, flagging different thread 
PID's as realtime (and also seeing what happens if I change the 
scheduler to RR instead of FIFO) and see what happens with the 
prebuffering pauses...

Gary