thanks for your response! I am aware that my description was not perfect, but I wanted to start somewhere.
In my software, the problem does not appear when I limit the frame rate to 5 FPS. With 100% GPU load it would achieve about 25 FPS on my laptop - including the mentioned problems.
I recognized the following: If I start a CUDA program like this one
I experience the same effect: the UI thread of Ubuntu gets slowed down. The GPU sheduling seems to suppress the UI thread.
Moreover, I run the "glmark2" benchmark. The glmark2 benchmark does not cause any problems or side-effects.
Perhaps the difference between Windows and Linux has to do with the Nvidia Optimus support by the NVidia drivers.
Currently, I am rendering the scene in every frame - no matter whether something got changed or not. I want to try to redraw the frame only when something got changed. This should limit the problem. Do you know whether there is an example for this in the Ardor3D examples project? As far as I have seen, all examples render the scene in every frame.
Thanks for your feedback!