change linux process priority

Question

I ran a jar file in Linux and it is running from last 3 days.

How can I change priority of that process? Will it speedup my application processing?

Answer 1

How can I change priority of that process?

renice priority [-p] pid

Useful priorities are: 20 (the affected processes will run only when nothing else in the system wants to), 0 (the ``base'' scheduling priority), anything negative (to make things go very fast)

Example: renice -5 -p 123, 123 is process PID, -5 is priority

Will it speedup my application processing?

No, if load average less number of CPU core.

Answer 2

You can change priority with renice command. It will speed up processing only if there are other applications actively consuming CPU time.

Answer 3

By default process priority in Linux is 0. Process priority can have any number between -20 to 19. Process priority can be set by using nice and modified using renice. -20 is the highest priority process and 19 is the lowest priority.

Here you're having a process already running and you want to change its priority. So you can enter the following command

renice -5 pid

where pid is the process id of the process whose priority you want to modify. To increase the priority of a process i.e. to set the priority value to a negative value, you need to be root user or use sudo.

Hope that helps.