CHRT(1)
NAME
chrt - manipulate real-time attributes of a process
SYNOPSIS
chrt [options] prio command [arg]... chrt [options] -p [prio] pid
DESCRIPTION
chrt(1) sets or retrieves the real-time scheduling attributes of an
existing PID or runs COMMAND with the given attributes. Both policy
(one of SCHED_OTHER, SCHED_FIFO, SCHED_RR, SCHED_BATCH, or SCHED_IDLE)
and priority can be set and retrieved.
The SCHED_BATCH policy is supported since Linux 2.6.16. The SCHED_IDLE
policy is supported since Linux 2.6.23.
OPTIONS
- -p, --pid
- operate on an existing PID and do not launch a new task
- -b, --batch
- set scheduling policy to SCHED_BATCH (Linux specific)
- -f, --fifo
- set scheduling policy to SCHED_FIFO
- -i, --idle
- set schedulng policy to SCHED_IDLE (Linux specific)
- -m, --max
- show minimum and maximum valid priorities, then exit
- -o, --other
- set policy scheduling policy to SCHED_OTHER
- -r, --rr
- set scheduling policy to SCHED_RR (the default)
- -h, --help
- display usage information and exit
- -v, --version
- output version information and exit
USAGE
- The default behavior is to run a new command::
- chrt prio command [arguments]
- You can also retrieve the real-time attributes of an existing task:
- chrt -p pid
- Or set them:
- chrt -p prio pid
PERMISSIONS
A user must possess CAP_SYS_NICE to change the scheduling attributes of
a process. Any user can retrieve the scheduling information.
NOTES
Only SCHED_FIFO, SCHED_OTHER and SCHED_RR are part of POSIX 1003.1b
Process Scheduling. The other scheduling attributes may be ignored on
some systems.
AUTHOR
Written by Robert M. Love.
COPYRIGHT
Copyright (C) 2004 Robert M. Love
This is free software; see the source for copying conditions. There is
NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE.
SEE ALSO
taskset(1), nice(1), renice(1)
See sched_setscheduler(2) for a description of the Linux scheduling
scheme.
AVAILABILITY
- The chrt command is part of the util-linux-ng package and is available
from ftp://ftp.kernel.org/pub/linux/utils/util-linux-ng/.