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/.