Linux renice command
On Unix-like operating systems, the renice command modifies the priority of running processes. It is similar to the nice command, but is used for processes that are already running.
This page describes the Linux version of renice.
Description
renice alters the scheduling priority of one or more running processes.
A higher value of priority actually makes the process lower priority; it means the process demands fewer system resources (and therefore is a "nicer" process). A lower priority value means the process demands more resources, possibly denying those resources to processes that are "nicer".
The priority value of any given process can vary from -20 (highest priority, least "nice") to 20 (lowest priority, "nicest"). The default priority of new processes, by default, is 0.
renice'ing a process group causes all processes in the process group to have their scheduling priority altered.
renice'ing a user causes all processes owned by the user to have their scheduling priority altered.
By default, the processes to be affected are specified by their process ID's.
Syntax
renice [-n] priority [[-p] pid who...] [[-g] pgrp who...] [[-u] user who...]
renice -h | -v
Options
| -n, --priority | The scheduling priority of the process, process group, or user. |
| -g, --pgrp | Force who parameters to be interpreted as process group ID's. |
| -u, --user | Force the who parameters to be interpreted as user names. |
| -p, --pid | Resets the who interpretation to be (the default) process ID's. |
| -v, --version | Display version information, and exit. |
| -h, --help | Display a help message, and exit. |
Priority
Users other than the superuser may only alter the priority of processes they own, and can only monotonically increase their "nice value" in the range 0 to PRIO_MAX (20). The superuser may alter the priority of any process and set the priority to any value in the range PRIO_MIN (-20) to PRIO_MAX.
Useful settings for priority are:
- 20: the affected processes run only when nothing else in the system needs the resources.
- 0: the default.
- any negative value: makes things go very fast, at the expense of other processes.
Examples
renice +1 987 -u daemon root -p 32
Change the priority of process IDs 987 and 32, and all processes owned by users daemon and root, to be one greater (+1, one increment "nicer") than its current value.
Related Commands
kill — Send a signal to a process, affecting its behavior or killing it.
nice — Invoke a command with an altered scheduling priority.
ps — Report the status of a process or processes.
top — Display a sortable, continually-updated list of processes.