Langue: en

Version: June 2010 (fedora - 01/12/10)

Section: 1 (Commandes utilisateur)


chrt - manipulate real-time attributes of a process


chrt [optionsprio command [arg]...
chrt [options] -p [priopid


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.

The SCHED_RESET_ON_FORK flag for policies SCHED_RR and SCHED_FIFO is supported since Linux 2.6.31.


-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)
-R, --reset-on-fork
add SCHED_RESET_ON_FORK flag to the SCHED_FIFO or SCHED_RR scheduling policy (Linux specific)
-v, --verbose
show status information
-h, --help
display usage information and exit
-V, --version
display version information and exit


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


A user must possess CAP_SYS_NICE to change the scheduling attributes of a process. Any user can retrieve the scheduling information.


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.


Written by Robert M. Love. Copyright © 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.


taskset(1), nice(1), renice(1)

See sched_setscheduler(2) for a description of the Linux scheduling scheme.


The chrt command is part of the util-linux-ng package and is available from