Changing the priority of a running process (renice command)

You can change the scheduling priority of a running process to a value lower or higher than the base scheduling priority by using the renice command from the command line. This command changes the nice value of a process.

Note: To run a process at a higher priority or to change the priority for a process that you did not start, you must have root user authority.
To change the priority of a running process, type the following:
renice Priority -p ProcessID
where Priority is a number in the range of -20 to 20. The higher the number, the lower the priority. If you use zero, the process will run at its base scheduling priority. ProcessID is the PID for which you want to change the priority.

You can also use the smit renice command to perform this task.