Back to main site | Back to man page index

CHRT(1)                                             User Commands                                             CHRT(1)



NAME
       chrt - manipulate the real-time attributes of a process

SYNOPSIS
       chrt [options] prio command [arg]...
       chrt [options] -p [prio] pid

DESCRIPTION
       chrt  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.

       The SCHED_RESET_ON_FORK flag for policies SCHED_RR and SCHED_FIFO is supported since Linux 2.6.31.

OPTIONS
       -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).

       -f, --fifo
              Set scheduling policy to SCHED_FIFO.

       -i, --idle
              Set scheduling 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.

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

       -r, --rr
              Set scheduling policy to SCHED_RR.  When policy is not defined the SCHED_RR is used as default.

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

       -v, --verbose
              Show status information.

       -h, --help
              Display usage information and exit.

       -V, --version
              Display version information and exit.

USAGE
       The default behavior is to run a new command:

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.

       Linux default scheduling policy is SCHED_OTHER.

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  MER‐
       CHANTABILITY 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   package   and   is  available  from  ftp://ftp.ker‐
       nel.org/pub/linux/utils/util-linux/.



util-linux                                            June 2010                                               CHRT(1)