[thirdparty/util-linux.git] / schedutils / chrt.1

.\" chrt(1) manpage
.\"
.\" Copyright (C) 2004 Robert Love
.\"
.\" This is free documentation; you can redistribute it and/or
.\" modify it under the terms of the GNU General Public License as
.\" published by the Free Software Foundation; either version 2 of
.\" the License.
.\"
.\" The GNU General Public License's references to "object code"
.\" and "executables" are to be interpreted as the output of any
.\" document formatting or typesetting system, including
.\" intermediate and printed output.
.\"
.\" This manual is distributed in the hope that it will be useful,
.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
.\" GNU General Public License for more details.
.\"
.\" You should have received a copy of the GNU General Public
.\" License along with this manual; if not, write to the Free
.\" Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111,
.\" USA.
.\"
.\" 2002-05-11 Robert Love <rml@tech9.net>
.\" 	Initial version
.\"
.TH CHRT "1" "Apr 2003" "schedutils" "Linux User's Manual"
.SH NAME
chrt \- manipulate real-time attributes of a process
.SH SYNOPSIS
.B chrt
.RI [ options ]\  prio
.IR command\  [ arg ]...
.br
.B chrt
.RI [ options ]
.B \-p
.RI [ prio ]\  pid
.SH DESCRIPTION
.PP
.BR chrt (1)
sets or retrieves the real-time scheduling attributes of an existing PID or
runs COMMAND with the given attributes.  Both policy (one of
.BR SCHED_OTHER ,
.BR SCHED_FIFO ,
.BR SCHED_RR ,
or
.BR SCHED_BATCH )
and priority can be set and retrieved.
.PP
The
.BR SCHED_BATCH
policy is supported since Linux 2.6.16.
.SH OPTIONS
.TP
.B -p, --pid
operate on an existing PID and do not launch a new task
.TP
.B -b, --batch
set scheduling policy to
.BR SCHED_BATCH
.TP
.B -f, --fifo
set scheduling policy to
.BR SCHED_FIFO
.TP
.B -m, --max
show minimum and maximum valid priorities, then exit
.TP
.B -o, --other
set policy scheduling policy to
.BR SCHED_OTHER
.TP
.B -r, --rr
set scheduling policy to
.BR SCHED_RR
(the default)
.TP
.B -h, --help
display usage information and exit
.TP
.B -v, --version
output version information and exit
.SH USAGE
.TP
The default behavior is to run a new command::
chrt prio command [arguments]
.TP
You can also retrieve the real-time attributes of an existing task:
chrt -p pid
.TP
Or set them:
chrt -p prio pid
.SH PERMISSIONS
A user must possess
.BR CAP_SYS_NICE
to change the scheduling attributes of a process.  Any user can retrieve the
scheduling information.
.SH AUTHOR
Written by Robert M. Love.
.SH COPYRIGHT
Copyright \(co 2004 Robert M. Love
.br
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
.SH "SEE ALSO"
.BR taskset (1),
.BR nice (1),
.BR renice (1)
.sp
See
.BR sched_setscheduler (2)
for a description of the Linux scheduling scheme.
.SH AVAILABILITY
The chrt command is part of the util-linux-ng package and is available from
ftp://ftp.kernel.org/pub/linux/utils/util-linux-ng/.
Commit	Line	Data
48d7b13a KZ	1	.\" chrt(1) manpage
	2	.\"
	3	.\" Copyright (C) 2004 Robert Love
	4	.\"
	5	.\" This is free documentation; you can redistribute it and/or
	6	.\" modify it under the terms of the GNU General Public License as
	7	.\" published by the Free Software Foundation; either version 2 of
	8	.\" the License.
	9	.\"
	10	.\" The GNU General Public License's references to "object code"
	11	.\" and "executables" are to be interpreted as the output of any
	12	.\" document formatting or typesetting system, including
	13	.\" intermediate and printed output.
	14	.\"
	15	.\" This manual is distributed in the hope that it will be useful,
	16	.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
	17	.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	18	.\" GNU General Public License for more details.
	19	.\"
	20	.\" You should have received a copy of the GNU General Public
	21	.\" License along with this manual; if not, write to the Free
	22	.\" Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111,
	23	.\" USA.
	24	.\"
	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
5ebbcdf9 LJ	33	.RI [ options ]\ prio
	34	.IR command\ [ arg ]...
	35	.br
	36	.B chrt
	37	.RI [ options ]
	38	.B \-p
	39	.RI [ prio ]\ pid
48d7b13a KZ	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
df3773fb	45	.BR SCHED_OTHER ,
48d7b13a KZ	46	.BR SCHED_FIFO ,
	47	.BR SCHED_RR ,
	48	or
df3773fb	49	.BR SCHED_BATCH )
48d7b13a	50	and priority can be set and retrieved.
09dd84ca KZ	51	.PP
	52	The
	53	.BR SCHED_BATCH
	54	policy is supported since Linux 2.6.16.
48d7b13a KZ	55	.SH OPTIONS
	56	.TP
	57	.B -p, --pid
	58	operate on an existing PID and do not launch a new task
df3773fb KZ	59	.TP
	60	.B -b, --batch
	61	set scheduling policy to
	62	.BR SCHED_BATCH
48d7b13a KZ	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::
697d58e8	88	chrt prio command [arguments]
48d7b13a KZ	89	.TP
48d7b13a KZ	90	You can also retrieve the real-time attributes of an existing task:
697d58e8	91	chrt -p pid
48d7b13a KZ	92	.TP
48d7b13a KZ	93	Or set them:
697d58e8	94	chrt -p prio pid
48d7b13a KZ	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.
48d7b13a KZ	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.
86d62711 KZ	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/.