NAME
chrt - manipulate real-time attributes of a process
SYNOPSIS
chrt [options] prio command [arg]... chrt [options] -p [prio] pid
DESCRIPTION
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.
OPTIONS
| -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) | |
| -h, --help | |
| display usage information and exit | |
| -v, --version | |
| output version information and exit | |
USAGE
| 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 | |
PERMISSIONS
A user must possess CAP_SYS_NICE to change the scheduling attributes of a process. Any user can retrieve the scheduling information.
NOTES
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.
AUTHOR
Written by Robert M. Love.
COPYRIGHT
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.
SEE ALSO
taskset(1), nice(1), renice(1)
See sched_setscheduler(2) for a description of the Linux scheduling scheme.
AVAILABILITY
The chrt command is part of the util-linux-ng package and is available from ftp://ftp.kernel.org/pub/linux/utils/util-linux-ng/.
