schedutils/chrt.1

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   3 .\" Copyright (C) 2004 Robert Love
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  25 .\" 2002-05-11 Robert Love <rml@tech9.net>
  26 .\"     Initial version
  27 .\"
  28 .TH CHRT "1" "Apr 2003" "schedutils" "Linux User's Manual"
  29 .SH NAME
  30 chrt \- manipulate real-time attributes of a process
  31 .SH SYNOPSIS
  32 .B chrt
  33 .RI [ options ]\  prio
  34 .IR command\  [ arg ]...
  35 .br
  36 .B chrt
  37 .RI [ options ]
  38 .B \-p
  39 .RI [ prio ]\  pid
  40 .SH DESCRIPTION
  41 .PP
  42 .BR chrt (1)
  43 sets or retrieves the real-time scheduling attributes of an existing PID or
  44 runs COMMAND with the given attributes.  Both policy (one of
  45 .BR SCHED_OTHER ,
  46 .BR SCHED_FIFO ,
  47 .BR SCHED_RR ,
  48 or
  49 .BR SCHED_BATCH )
  50 and priority can be set and retrieved.
  51 .PP
  52 The
  53 .BR SCHED_BATCH
  54 policy is supported since Linux 2.6.16.
  55 .SH OPTIONS
  56 .TP
  57 .B -p, --pid
  58 operate on an existing PID and do not launch a new task
  59 .TP
  60 .B -b, --batch
  61 set scheduling policy to
  62 .BR SCHED_BATCH
  63 .TP
  64 .B -f, --fifo
  65 set scheduling policy to
  66 .BR SCHED_FIFO
  67 .TP
  68 .B -m, --max
  69 show minimum and maximum valid priorities, then exit
  70 .TP
  71 .B -o, --other
  72 set policy scheduling policy to
  73 .BR SCHED_OTHER
  74 .TP
  75 .B -r, --rr
  76 set scheduling policy to
  77 .BR SCHED_RR
  78 (the default)
  79 .TP
  80 .B -h, --help
  81 display usage information and exit
  82 .TP
  83 .B -v, --version
  84 output version information and exit
  85 .SH USAGE
  86 .TP
  87 The default behavior is to run a new command::
  88 chrt prio command [arguments]
  89 .TP
  90 You can also retrieve the real-time attributes of an existing task:
  91 chrt -p pid
  92 .TP
  93 Or set them:
  94 chrt -p prio pid
  95 .SH PERMISSIONS
  96 A user must possess
  97 .BR CAP_SYS_NICE
  98 to change the scheduling attributes of a process.  Any user can retrieve the
  99 scheduling information.
 100 .SH AUTHOR
 101 Written by Robert M. Love.
 102 .SH COPYRIGHT
 103 Copyright \(co 2004 Robert M. Love
 104 .br
 105 This is free software; see the source for copying conditions.  There is NO
 106 warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 107 .SH "SEE ALSO"
 108 .BR taskset (1),
 109 .BR nice (1),
 110 .BR renice (1)
 111 .sp
 112 See
 113 .BR sched_setscheduler (2)
 114 for a description of the Linux scheduling scheme.
 115 .SH AVAILABILITY
 116 The chrt command is part of the util-linux-ng package and is available from
 117 ftp://ftp.kernel.org/pub/linux/utils/util-linux-ng/.