kpm performs three types of process management:
Renice allows users to change the priority of their processes, as described here. By selecting Process->Renice... (Ctrl-r), users can decrease the priority of their processes. Additionally, the super-user can increase or decrease the priority of any process.
The super-user can change the scheduling of processes, as described here. This is done by selecting Process->Change Scheduling... (Ctrl-s).
Users can send any of the POSIX signals listed here to their processes. Additionally, the super-user can send any of those signals to any process. Those signals are sent using Signal, as described here.