chrt(1) manpage Copyright (C) 2004 Robert Love Copyright (C) 2015 Karel Zak <firstname.lastname@example.org> This is free documentation; you can redistribute it and/or modify it under the terms of the GNU General Public License, version 2, as published by the Free Software Foundation. The GNU General Public License's references to "object code" and "executables" are to be interpreted as the output of any document formatting or typesetting system, including intermediate and printed output. This manual is...
NAMEchrt - manipulate the real-time attributes of a process
SYNOPSISchrt [options] priority command [argument...]
chrt [options] -p [priority] pid
chrt sets or retrieves the real-time scheduling attributes of an existing 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.
- -a, --all-tasks
- Set or retrieve the scheduling attributes of all the tasks (threads) for a given PID.
- -b, --batch
- Set scheduling policy to SCHED_BATCH (Linux-specific). The priority argument has to be set to zero.
- -f, --fifo
- Set scheduling policy to SCHED_FIFO.
- -i, --idle
- Set scheduling policy to SCHED_IDLE (Linux-specific). The priority argument has to be set to zero.
- -m, --max
- Show minimum and maximum valid priorities, then exit.
- -o, --other
- Set policy scheduling policy to SCHED_OTHER.
- -p, --pid
- Operate on an existing PID and do not launch a new task.
- -R, --reset-on-fork
- Add SCHED_RESET_ON_FORK flag to the SCHED_FIFO or SCHED_RR scheduling policy (Linux-specific).
- -r, --rr
- Set scheduling policy to SCHED_RR. When policy is not defined the SCHED_RR is used as default.
- -v, --verbose
- Show status information.
- -V, --version
- Display version information and exit.
- -h, --help
- 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
PERMISSIONSA user must possess CAP_SYS_NICE to change the scheduling attributes of a process. Any user can retrieve the scheduling information.
NOTESOnly 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.
SEE ALSOtaskset(1), nice(1), renice(1)
See sched_setscheduler(2) for a description of the Linux scheduling scheme.