[GEM-dev] Weird performance issues when using Pd, Gem, and realtime-lsm on Linux

[Ivica Ico Bukvic]

Greetings all (again :-),

I have another peculiarity I've encountered on my machine. This was not a
problem on non-Ubuntu setup, so it is likely something specific to my
configuration. Yet, I am at a loss as to what may be the cause of this.

I am using 32-bit Ubuntu Hoary, Pd 0.38, Gem 0.90, h/w is eMachines M6807
(AMD64) laptop with the latest BIOS installed. Video driver is fglrx
(proprietary ATI) on top of X.org.

I've installed realtime-lsm and it works fine (good latency via jack etc.).
It is using default settings. The kernel in quesiton is 2.6.10. Pd also runs
fine, *except* in the following 2 scenarios:

1) When running as a root or non-root user with -rt flag and I start any Gem
example, once the Gem window is created *and* enabled, if I move any open
window (Pd-related or non-Pd-related), the system starts hanging for a
couple of seconds, then I guess the pd watchdog kicks in (albeit extremely
sporadically) and allows me a split second to release mouse button (or click
a couple times as if the release I made during the hanging process did not
get registered properly) and if I am lucky the hick-up stops (the cpu usage
during the hang is 100%). By this time my dragged window usually shows up
somewhere else on the desktop. If I do not move the window, everything is
fine. Clicking on the buttons/options inside the patch is not a problem as
well as doing anything else on computer.

Ironically, when running Pd without -rt flag, there are no problems
whatsoever of this kind (could it be that perhaps Gem somehow is not quite
aware of the realtime-lsm behavior or something like this in respect to X
server, so it supersedes the X server itself in importance, or something
like that?).

2) When trying to play Gem examples that use prerecorded movies as textures
of the OpenGL objects. Trying to play videos (by sending "auto" option, like
in ../gem/examples/04.pix/movie.pd) eats so much resources in user mode that
I have to kill the X server (sometimes I have to even forcefully shut the
machine down). Cycling through the frames using the frame number
inlet/counter (right inlet on pix_movie) is no problem whatsoever. Using the
same patch as root allows everything to proceed but at an extremely low
framerate (the video card is ATI mobility 9600 so this should not be an
issue), i.e. 0.5 frames/sec. Again, manually cycling through the frames via
the frame number inlet (I guess one could use metro for this) is a breeze as
long as the "auto" is turned off. When trying to run patches which utilize
movies I get the following messages depending upon the movie format:
.avi file: <ffindeo3> : doesn't support DR1
.mpg file:
mpeg3video_seek: frame accurate seeking without a table of contents
is no longer supported.  Use mpeg3toc <mpeg file> <table of contents>
to generate a table of contents and load the table of contents instead.
.mov is fine.

Doing the same thing without the -rt flag makes playing of the movie
painfully slow (similar like when running as a root), but again when using
frame counter instead it's an absolute breeze no matter how quickly you
cycle through the frames.

At any rate, I would greatly appreciate any help I can get regarding these
two issues.

Best wishes,

Ico
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