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renice - Man Page

alter priority of running processes

Examples (TL;DR)

Synopsis

renice [--priority|--relative] priority [-g|-p|-u] identifier...

Description

renice alters the scheduling priority of one or more running processes. The first argument is the priority value to be used. The other arguments are interpreted as process IDs (by default), process group IDs, user IDs, or user names. 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.

If no -n, --priority or --relative option is used, then the priority is set as absolute.

Options

-n priority

Specify the absolute or relative (depending on environment variable POSIXLY_CORRECT) scheduling priority to be used for the process, process group, or user. Use of the option -n is optional, but when used, it must be the first argument. See Notes for more information.

--priority priority

Specify an absolute scheduling priority. Priority is set to the given value. This is the default, when no option is specified.

--relative priority

Specify a relative scheduling priority. Same as the standard POSIX -n option. Priority gets incremented/decremented by the given value.

-g,  --pgrp

Interpret the succeeding arguments as process group IDs.

-p,  --pid

Interpret the succeeding arguments as process IDs (the default).

-u,  --user

Interpret the succeeding arguments as usernames or UIDs.

-h,  --help

Display help text and exit.

-V,  --version

Print version and exit.

Files

/etc/passwd

to map user names to user IDs

Notes

Users other than the superuser may only alter the priority of processes they own. Furthermore, an unprivileged user can only increase the "nice value" (i.e., choose a lower priority) and such changes are irreversible unless (since Linux 2.6.12) the user has a suitable "nice" resource limit (see ulimit(1p) and getrlimit(2)).

The superuser may alter the priority of any process and set the priority to any value in the range -20 to 19. Useful priorities are: 19 (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).

For historical reasons in this implementation, the -n option did not follow the POSIX specification. Therefore, instead of setting a relative priority, it sets an absolute priority by default. As this may not be desirable, this behavior can be controlled by setting the environment variable POSIXLY_CORRECT to be fully POSIX compliant. See the -n option for details. See --relative and --priority for options that do not change behavior depending on environment variables.

History

The renice command appeared in 4.0BSD.

Examples

The following command would change the priority of the processes with PIDs 987 and 32, plus all processes owned by the users daemon and root:

renice +1 987 -u daemon root -p 32

See Also

nice(1), chrt(1), getpriority(2), setpriority(2), credentials(7), sched(7)

Reporting Bugs

For bug reports, use the issue tracker at https://github.com/util-linux/util-linux/issues.

Availability

The renice command is part of the util-linux package which can be downloaded from Linux Kernel Archive.

Referenced By

chrt(1), conntrackd.conf(5), getpriority(2), nice(1), nice(2), skill(1), taskset(1), uclampset(1).

2024-04-24 util-linux 2.40.1