Do not show kernel threads by default

[baryluk]

On modern systems, especially with a lot of CPU cores, kernel can have a lot of own tasks / threads, that are almost never of interest to casual user, or even expert.

On my system there are 386 (yes!), kernel threads. I have zero interest in any of them, unless something is really really wrong. In which case, I will use other tools than mate-system-monitor to troubleshoot anyway. I still want to see all user space processes (including that of root, and other userspace users / daemons, etc), so I can't just switch to "My processes" only.

It would be good to have option to hide kernel tasks and threads, and enable it by default to not show them. It would also speed up GUI updates quite a bit.

So, instead of showing me 534 processes, the mate-system-monitor will show me now 148 processes, which is quite manageable to scroll, comprehend and update in performant way.

I don't know how procps does detect the kernel threads, but it does, and show them differently (in square brackets). I believe the trick is to do readlink on /proc/<PID>/exe and/or /proc/<PID>/cwd and/or /proc/<PID>/root. If the result is empty string (""), and the uid (from /proc/<PID>/stat or proc/<PID>/status) is 0, then it is a kernel process / task / thread.

[rbuj]

You can check the option Dependencies, next collapse and expand all trees for grouping kernel processes, kthreadadd in the picture below:

[baryluk]

You can check the option Dependencies, next collapse and expand all trees for grouping kernel processes, kthreadadd in the picture below:

I don't want to use Dependencies option. I want a flat view.