Processes fall into distinct classes with a separate scheduling policy applied to each class.
In the default configuration, a runnable real-time process runs before any other process. Therefore, inappropriate use of real-time processes can have a dramatic negative impact on system performance. If an idlist is present it must appear last on the command line and the elements of the list must be separated by white space. If no idlist is present an idtype argument of pid, ppid, pgid, sid, class, uid, or gid specifies the process ID, parent process ID, process group ID, session ID, class, user ID, or group ID, respectively, of the priocntl command itself. The -c class option specifies the class to be set.