Scroll to navigation

CHRT(1) User Commands CHRT(1)


chrt - manipulate the real-time attributes of a process


chrt [options] priority command [argument...]
chrt [options] -p [prioritypid


chrt sets or retrieves the real-time scheduling attributes of an existing pid, or runs command with the given attributes.


Set scheduling policy to SCHED_OTHER. This is the default Linux scheduling policy.
Set scheduling policy to SCHED_FIFO.
Set scheduling policy to SCHED_RR. When no policy is defined, the SCHED_RR is used as the default.
Set scheduling policy to SCHED_BATCH (Linux-specific, supported since 2.6.16). The priority argument has to be set to zero.
Set scheduling policy to SCHED_IDLE (Linux-specific, supported since 2.6.23). The priority argument has to be set to zero.
Set scheduling policy to SCHED_DEADLINE (Linux-specific, supported since 3.14). The priority argument has to be set to zero. See also --sched-runtime, --sched-deadline and --sched-period. The relation between the options required by the kernel is runtime <= deadline <= period. chrt copies period to deadline if --sched-deadline is not specified and deadline to runtime if --sched-runtime is not specified. It means that at least --sched-period has to be specified. See sched(7) for more details.


Specifies runtime parameter for SCHED_DEADLINE policy (Linux-specific).
Specifies period parameter for SCHED_DEADLINE policy (Linux-specific).
Specifies deadline parameter for SCHED_DEADLINE policy (Linux-specific).
Add SCHED_RESET_ON_FORK flag to the SCHED_FIFO or SCHED_RR scheduling policy (Linux-specific, supported since 2.6.31).


Set or retrieve the scheduling attributes of all the tasks (threads) for a given PID.
Show minimum and maximum valid priorities, then exit.
Operate on an existing PID and do not launch a new task.
Show status information.
Display version information and exit.
Display help text and exit.


chrt priority command [arguments]
chrt -p pid
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 some systems.

Linux' default scheduling policy is SCHED_OTHER.


Robert Love
Karel Zak


nice(1), renice(1), taskset(1), sched(7)

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


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

January 2016 util-linux