「chrt」-

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chrt – manipulate the real-time attributes of a process

命令语法格式

chrt [options] priority command [argument…]

chrt [options] -p [priority] pid

命令描述

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

POLICIES

-o, –other
Set scheduling policy to SCHED_OTHER. This is the default Linux scheduling policy.

-f, –fifo
Set scheduling policy to SCHED_FIFO.

-r, –rr
Set scheduling policy to SCHED_RR. When no policy is defined, the SCHED_RR is used as the default.

-b, –batch
Set scheduling policy to SCHED_BATCH (Linux-specific, supported since 2.6.16). The priority argument has to be set to zero.

-i, –idle
Set scheduling policy to SCHED_IDLE (Linux-specific, supported since 2.6.23). The priority argument has to be set to zero.

-d, –deadline
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.

SCHEDULING OPTIONS

-T, –sched-runtime nanoseconds
Specifies runtime parameter for SCHED_DEADLINE policy (Linux-specific).

-P, –sched-period nanoseconds
Specifies period parameter for SCHED_DEADLINE policy (Linux-specific).

-D, –sched-deadline nanoseconds
Specifies deadline parameter for SCHED_DEADLINE policy (Linux-specific).

-R, –reset-on-fork
Add SCHED_RESET_ON_FORK flag to the SCHED_FIFO or SCHED_RR scheduling policy (Linux-specific, supported since 2.6.31).

命令支持的选项及含义

-a, –all-tasks
Set or retrieve the scheduling attributes of all the tasks (threads) for a given PID.

-m, –max
Show minimum and maximum valid priorities, then exit.

-p, –pid
Operate on an existing PID and do not launch a new task.

-v, –verbose
Show status information.

-V, –version
Display version information and exit.

-h, –help
Display help text and exit.

USAGE

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

PERMISSIONS

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

注意事项

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.

相关手册

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

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

AUTHORS

Robert Love ⟨
rml@tech9.net

Karel Zak ⟨
kzak@redhat.com

AVAILABILITY

The chrt command is part of the util-linux package and is available from
https://www.kernel.org/pub/linux/utils/util-linux/.

参考文献

  • man 1 chrt, Version chrt from util-linux 2.32

更新日志

  • 07/11/2018 创建文章