Is it possible to set a new
nice level of a running process with a known id?
Does this operation require root access, or just being the owner of the process?
If you're at a terminal you can use
renice [-n] priority [[-p] pid ...] [[-g] pgrp ...] [[-u] user ...]
A simple example would be
renice 8 31043 31043: old priority 5, new priority 8
You can also pass it hard flags, but it follows that order (you have to pass priority first and then the pid - if you change the order it will show the usage messagge)
renice -n 5 -p 31043 31043: old priority 8, new priority 5
Priorities work on a scale of
19 - The lower the number, the higher it's priority on the system.
If you own the process then you won't need root - however, if the process is owned by another user or if you plan on changing the group/user of the process root (via
sudo) will be required.
Prior to 11.04: System > Administration > System Monitor. Choose Processes.
In 11.04: Alt+A and search for
The id's are shown in the image here:
And nice does not require sudo for increasing niceness if you own the task. It does if you need to decrease niceness.
nice -n 19 your_command
renice 19 $(pidof your_command_name_like_for_ex_ffmpeg)
between -20 and 19
19 is lowest priority
Usage of "renice" in terminal is as follows:
Usage: renice [-n] <priority> [-p] <pid> [<pid> ...] renice [-n] <priority> [-g] <pgrp> [<pgrp> ...] renice [-n] <priority> [-u] <user> [<user> ...] Options: -g, --pgrp <id> interpret as process group ID -h, --help print help -n, --priority <num> set the nice increment value -p, --pid <id> force to be interpreted as process ID -u, --user <name|id> interpret as username or user ID -v, --version print version
Using "sudo" before command "renice" elevates user to root level and an admin/root password will be required.
So e.g. if you want to elevate process with PID (process ID) 2606 from Normal priority to High priority, you would type in terminal as follows:
sudo renice -n -5 -p 2606
You can also renice a process within top.
1) Start top
2) renice by pressing
r. You will be prompted for the Process ID (PID) of the process you wish to renice. The default PID is the first process (one consuming the most resources). Confirm with Enter. Set the new nice value from -20 (higher priority) to +19 (lower priority).