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 exist‐
       ing pid, or runs command with the given attributes.  Both  policy  (one
       of  SCHEDOTHER,  SCHEDFIFO, SCHEDRR, SCHEDBATCH, or SCHEDIDLE) and
       priority can be set and retrieved.

       The SCHEDBATCH policy is supported since Linux 2.6.16.  The SCHEDIDLE
       policy is supported since Linux 2.6.23.

       The  SCHEDRESETONFORK  flag  for policies SCHEDRR and SCHEDFIFO 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 SCHEDBATCH (Linux specific).

       -f, fifo
              Set scheduling policy to SCHEDFIFO.

       -i, idle
              Set scheduling policy to SCHEDIDLE (Linux specific).

       -m, max
              Show minimum and maximum valid priorities, then exit.

       -o, other
              Set policy scheduling policy to SCHEDOTHER.

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

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

       -R, reset-on-fork
              Add SCHEDRESETONFORK  flag  to  the  SCHEDFIFO  or  SCHEDRR
              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:
              chrt prio command [arguments]

       You can also retrieve the real-time attributes of an existing task:
              chrt -p pid

       Or set them:
              chrt -r -p prio pid

PERMISSIONS
       A user must possess CAPSYSNICE to change the scheduling attributes of
       a process.  Any user can retrieve the scheduling information.

NOTES
       Only SCHEDFIFO, SCHEDOTHER and SCHEDRR are  part  of  POSIX  1003.1b
       Process  Scheduling.  The other scheduling attributes may be ignored on
       some systems.

       Linux default scheduling policy is SCHEDOTHER.

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 schedsetscheduler(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.kernel.org/pub/linux/utils/util-linux/.



util-linux                         June 2010                           CHRT(1)