3 .\" Copyright (C) 2004 Robert Love
4 .\" Copyright (C) 2015 Karel Zak <kzak@redhat.com>
6 .\" This is free documentation; you can redistribute it and/or
7 .\" modify it under the terms of the GNU General Public License,
8 .\" version 2, as published by the Free Software Foundation.
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15 .\" This manual is distributed in the hope that it will be useful,
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17 .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 .\" GNU General Public License for more details.
20 .\" You should have received a copy of the GNU General Public License along
21 .\" with this program; if not, write to the Free Software Foundation, Inc.,
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24 .TH CHRT 1 "January 2016" "util-linux" "User Commands"
26 chrt \- manipulate the real-time attributes of a process
30 .IR priority\ command\ [ argument ...]
39 sets or retrieves the real-time scheduling attributes of an existing \fIpid\fR,
40 or runs \fIcommand\fR with the given attributes.
44 \fB\-o\fR, \fB\-\-other\fR
45 Set scheduling policy to
47 This is the default Linux scheduling policy.
49 \fB\-f\fR, \fB\-\-fifo\fR
50 Set scheduling policy to \fBSCHED_FIFO\fR.
52 \fB\-r\fR, \fB\-\-rr\fR
53 Set scheduling policy to
55 When no policy is defined, the
57 is used as the default.
59 \fB\-b\fR, \fB\-\-batch\fR
60 Set scheduling policy to
62 (Linux-specific, supported since 2.6.16). The priority argument has to be set to zero.
64 \fB\-i\fR, \fB\-\-idle\fR
65 Set scheduling policy to
67 (Linux-specific, supported since 2.6.23). The priority argument has to be set to zero.
70 Set scheduling policy to
72 (Linux-specific, supported since 3.14). The priority argument has to be set to zero.
73 See also \fB\-\-sched\-runtime\fR, \fB\-\-sched\-deadline\fR and
74 \fB\-\-sched\-period\fR. The relation between the options required by the kernel is
75 runtime <= deadline <= period.
77 copies \fIperiod\fR to \fIdeadline\fR if \fB\-\-sched\-deadline\fR is not specified and
78 \fIdeadline\fR to \fIruntime\fR if \fB\-\-sched\-runtime\fR is not specified.
79 It means that at least \fB\-\-sched\-period\fR has to be specified. See
83 .SH "SCHEDULING OPTIONS"
85 \fB\-T\fR, \fB\-\-sched\-runtime\fR \fInanoseconds\fR
86 Specifies runtime parameter for SCHED_DEADLINE policy (Linux-specific).
88 \fB\-P\fR, \fB\-\-sched\-period\fR \fInanoseconds\fR
89 Specifies period parameter for SCHED_DEADLINE policy (Linux-specific).
91 \fB\-D\fR, \fB\-\-sched\-deadline\fR \fInanoseconds\fR
92 Specifies deadline parameter for SCHED_DEADLINE policy (Linux-specific).
94 \fB\-R\fR, \fB\-\-reset-on-fork\fR
96 .B SCHED_RESET_ON_FORK
101 scheduling policy (Linux-specific, supported since 2.6.31).
105 .BR -a ,\ --all-tasks
106 Set or retrieve the scheduling attributes of all the tasks (threads) for a
110 Show minimum and maximum valid priorities, then exit.
113 Operate on an existing PID and do not launch a new task.
116 Show status information.
119 Display version information and exit.
122 Display help text and exit.
125 The default behavior is to run a new command:
128 .IR command\ [ arguments ]
130 You can also retrieve the real-time attributes of an existing task:
140 to change the scheduling attributes of a process. Any user can retrieve the
141 scheduling information.
149 are part of POSIX 1003.1b Process Scheduling. The other scheduling attributes
150 may be ignored on some systems.
152 Linux' default scheduling policy is
161 .BR sched_setscheduler (2)
162 for a description of the Linux scheduling scheme.
172 The chrt command is part of the util-linux package and is available from
173 ftp://ftp.kernel.org/pub/linux/utils/util-linux/.