CHRT

Section: Linux User's Manual (1)
Updated: Apr 2003
Index Return to Main Contents
 

NAME

chrt - manipulate real-time attributes of a process  

SYNOPSIS

chrt [optionsprio command [arg]...
chrt [options] -p [priopid  

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/.


 

Index

NAME
SYNOPSIS
DESCRIPTION
OPTIONS
USAGE
PERMISSIONS
NOTES
AUTHOR
COPYRIGHT
SEE ALSO
AVAILABILITY

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