1CHRT(1)                          User Commands                         CHRT(1)
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NAME

6       chrt - manipulate the real-time attributes of a process
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SYNOPSIS

9       chrt [options] prio command [arg]...
10       chrt [options] -p [prio] pid
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DESCRIPTION

13       chrt sets or retrieves the real-time scheduling attributes of an exist‐
14       ing pid, or runs command with the given attributes.  Both  policy  (one
15       of  SCHED_OTHER,  SCHED_FIFO, SCHED_RR, SCHED_BATCH, or SCHED_IDLE) and
16       priority can be set and retrieved.
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18       The SCHED_BATCH policy is supported since Linux 2.6.16.  The SCHED_IDLE
19       policy is supported since Linux 2.6.23.
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21       The  SCHED_RESET_ON_FORK  flag  for policies SCHED_RR and SCHED_FIFO is
22       supported since Linux 2.6.31.
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OPTIONS

25       -a, --all-tasks
26              Set or retrieve the  scheduling  attributes  of  all  the  tasks
27              (threads) for a given PID.
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29       -b, --batch
30              Set scheduling policy to SCHED_BATCH (Linux specific).
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32       -f, --fifo
33              Set scheduling policy to SCHED_FIFO.
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35       -i, --idle
36              Set scheduling policy to SCHED_IDLE (Linux specific).
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38       -m, --max
39              Show minimum and maximum valid priorities, then exit.
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41       -o, --other
42              Set policy scheduling policy to SCHED_OTHER.
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44       -p, --pid
45              Operate on an existing PID and do not launch a new task.
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47       -r, --rr
48              Set  scheduling  policy to SCHED_RR.  When policy is not defined
49              the SCHED_RR is used as default.
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51       -R, --reset-on-fork
52              Add SCHED_RESET_ON_FORK  flag  to  the  SCHED_FIFO  or  SCHED_RR
53              scheduling policy (Linux specific).
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55       -v, --verbose
56              Show status information.
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58       -h, --help
59              Display usage information and exit.
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61       -V, --version
62              Display version information and exit.
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USAGE

65       The default behavior is to run a new command:
66              chrt prio command [arguments]
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68       You can also retrieve the real-time attributes of an existing task:
69              chrt -p pid
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71       Or set them:
72              chrt -r -p prio pid
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PERMISSIONS

75       A user must possess CAP_SYS_NICE to change the scheduling attributes of
76       a process.  Any user can retrieve the scheduling information.
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NOTES

79       Only SCHED_FIFO, SCHED_OTHER and SCHED_RR are  part  of  POSIX  1003.1b
80       Process  Scheduling.  The other scheduling attributes may be ignored on
81       some systems.
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83       Linux default scheduling policy is SCHED_OTHER.
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AUTHOR

86       Written by Robert M. Love.
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89       Copyright © 2004 Robert M. Love
90       This is free software; see the source for copying conditions.  There is
91       NO  warranty;  not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
92       PURPOSE.
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SEE ALSO

95       taskset(1), nice(1), renice(1)
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97       See sched_setscheduler(2) for a description  of  the  Linux  scheduling
98       scheme.
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AVAILABILITY

101       The  chrt  command  is  part of the util-linux package and is available
102       from ftp://ftp.kernel.org/pub/linux/utils/util-linux/.
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106util-linux                         June 2010                           CHRT(1)
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