[mythtv-users] Strange X CPU usage for 720p input streams
Paul Robertson
paulrobertson at swbell.net
Fri Jun 30 13:46:06 UTC 2006
My system config is very similar (Athlon 2200+, Nvidia 5200FX, 512MB, FC5,
gnome), and I have been struggling with this same issue for some time. Here
is some CPU usage data I collected to illustrate:
Source %frontend %Xorg %Idle
----------- ------------- -------- -------
480 SD 10 0.5 85
720p HD 40 59 1
1080i HD 35 0.5 62
Note the high % CPU usage for Xorg when running 720p. I have tried a lot
of experiments to try and isolate, but without much luck.
Try 1) I am using the 8178 nvidia driver currently, but tried both older
and more recent versions. Same result.
Try 2) Adjusted all settings available in nvidia-settings configuration
tool, .nothing made a difference
Try 3) I'm using xrandr to set display size to exactly match source on play
back. Above numbers were taken this way. If I don't do this, the Xorg %CPU
usage goes up dramatically for all cases. I presume this is due to overhead
required to scale the output. .so reverse logic would make me think maybe
720p is getting scaled some how despite the fact I am displaying it on
720x1280.
Try 4) Tried KDE instead of GNOME, same. Also tried running X with a
simple window manager, like tvm. Although initially this appeared to fix
the problem, it did not.
Try 5 ) 720x1280 is what I run my mythtv menus at. Hmm..., coincidence
maybe? .so changed my default gnome desktop size and mythtv menus to
480x720. Made no difference.
Initially had this setup running with a Athlon 1100 and had same issue.
This is what prompted me to swap in a faster processor, but it made no
difference.
Any ideas?
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