[mythtv-users] Real-time priority threads

Jan Ceuleers jan.ceuleers at gmail.com
Sat Apr 9 08:23:12 UTC 2011


I need some help with getting mythfrontend to use real-time priority 
during playback. I've been googling like crazy and can't find what I'm 
doing wrong.

- I have verified that the user running the frontend is a member of the 
audio group:

root at fe2:~# grep audio < /etc/group

- I have verified that the audio group is permitted to request real-time 

root at fe2:~# grep rtprio < /etc/security/limits.conf
#        - rtprio - max realtime priority
*		-	rtprio	0
@audio		-	rtprio	50

- I have in fact verified that these limits do indeed make it 
(presumably through pam_limits.so) to the video playback thread:

root at fe2:~# grep realtime < /proc/30790/limits
Max realtime priority     50                   50
Max realtime timeout      unlimited            unlimited            us 

Yet I can see in htop that this thread is not operating under real-time 
priority, whereas certain other threads on the same system are. For 
example, I have started ntpd with the -N option and as a result it does 
show up as RT in htop.

Before upgrading to 0.24 (detailed version info below) I used to get the 
following line in the frontend log:

2011-04-02 21:09:01.651 Using realtime priority.

Not anymore.

And yes, the "Enable realtime priority threads" flag is checked on the 
General Playback (1/8) screen of Setup -> TV Settings -> Playback.

root at fe2:~# mythfrontend --version
xprop:  unable to open display ''
Please attach all output as a file in bug reports.
MythTV Version   : v0.24-236-g362d834
MythTV Branch    : fixes/0.24
Network Protocol : 63
Library API      : 0.24.20101129-1
QT Version       : 4.6.2
Options compiled in:
  linux debug using_alsa using_oss using_pulse using_pulseoutput 
using_backend using_bindings_perl using_bindings_python using_directfb 
using_dvb using_firewire using_frontend using_hdhomerun using_hdpvr 
using_iptv using_ivtv using_joystick_menu using_lirc using_mheg 
using_opengl_video using_opengl_vsync using_qtdbus using_qtwebkit 
using_v4l using_x11 using_xrandr using_xv using_bindings_perl 
using_bindings_python using_mythtranscode using_opengl using_vdpau 
using_ffmpeg_threads using_live using_mheg

root at fe2:~# uname -a
Linux fe2 2.6.32-30-generic #59-Ubuntu SMP Tue Mar 1 21:30:21 UTC 2011 
i686 GNU/Linux

Thanks for any hints.


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