My experience on GNOME is that programs running slowly can completely freeze all other desktop windows.
For example, if I load a very large file in gedit everything may freeze up pretty rapidly.
I’ve had many more subtle cases of it though where one program is doing spiky processing and the whole desktop is unresponsive.
Other desktop environments like MacOS or Windows seem to cope with the situation much better. For example on MacOS the program’s windows would freeze, but other windows would continue to function. Obviously the program could continue to use up system resources until everything hangs, but that takes a while to happen, and the user can force close the application before that happens.
I honestly have no idea what discussions the Linux community is having on this topic, but it seems very important. It was an issue when I used Linux desktop 10 years ago and still is. My objective is to try and foster a conversation around making Linux better, not ragging on Linux.
The kernel must be handling multi-tasking well. No doubt multitasking optimization is something kernel devs put a lot of work in to. Servers I manage don’t really have a problem unless I trigger a much more explicitly bad situation (i.e. creating some kind of I/O bottleneck in MySQL that results in locks that results in queue explosion that results in process explosion).
I’m sure there must be some complex problem to solve here, but I don’t know what it is, and I think we need to make progress on solving whatever it is.
Who can fill me in?