CHRT(1) User Commands CHRT(1)
chrt – manipulate the real-time attributes of a process
chrt [options] priority command [argument…] chrt [options] -p [priority] pid
chrt sets or retrieves the real-time scheduling attributes of an exist‐
ing pid, or runs command with the given attributes. Both the policy
(one of SCHED_OTHER, SCHED_FIFO, SCHED_RR, SCHED_BATCH, or SCHED_IDLE)
and the 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.
Set or retrieve the scheduling attributes of all the tasks
(threads) for a given PID.
Set scheduling policy to SCHED_BATCH (Linux-specific). The pri‐
ority argument has to be set to zero.
Set scheduling policy to SCHED_FIFO.
Set scheduling policy to SCHED_IDLE (Linux-specific). The prior‐
ity argument has to be set to zero.
Show minimum and maximum valid priorities, then exit.
Set policy scheduling policy to SCHED_OTHER.
Operate on an existing PID and do not launch a new task.
Add SCHED_RESET_ON_FORK flag to the SCHED_FIFO or SCHED_RR
scheduling policy (Linux-specific).
Set scheduling policy to SCHED_RR. When policy is not defined
the SCHED_RR is used as default.
Show status information.
Display version information and exit.
Display help text and exit.
The default behavior is to run a new command:
chrt priority command [arguments]
You can also retrieve the real-time attributes of an existing task:
chrt -p pid
Or set them:
chrt -r -p priority 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
Linux default scheduling policy is SCHED_OTHER.
See sched_setscheduler(2) for a description of the Linux scheduling
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 MER‐
CHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
The chrt command is part of the util-linux package and is available
util-linux August 2014 CHRT(1)