Section (1) chrt
Name
chrt — manipulate the real-time attributes of a process
Synopsis
chrt [options] priority
command [ argument... ]
chrt [options] −p [priority] pid
DESCRIPTION
chrt sets or
retrieves the real-time scheduling attributes of an existing
pid, or runs
command with the
given attributes.
POLICIES
−o,−−other-
Set scheduling policy to
SCHED_OTHER. This is the default Linux scheduling policy. −f,−−fifo-
Set scheduling policy to
SCHED_FIFO. −r,−−rr-
Set scheduling policy to
SCHED_RR. When no policy is defined, theSCHED_RRis used as the default. −b,−−batch-
Set scheduling policy to
SCHED_BATCH(Linux-specific, supported since 2.6.16). The priority argument has to be set to zero. −i,−−idle-
Set scheduling policy to
SCHED_IDLE(Linux-specific, supported since 2.6.23). The priority argument has to be set to zero. −d, −−deadline-
Set scheduling policy to
SCHED_DEADLINE(Linux-specific, supported since 3.14). The priority argument has to be set to zero. See also−−sched−runtime,−−sched−deadlineand−−sched−period. The relation between the options required by the kernel is runtime <= deadline <= period. chrt copies period to deadline if−−sched−deadlineis not specified and deadline to runtime if−−sched−runtimeis not specified. It means that at least−−sched−periodhas to be specified. See sched(7) for more details.
SCHEDULING OPTIONS
−T,−−sched−runtimenanoseconds-
Specifies runtime parameter for SCHED_DEADLINE policy (Linux-specific).
−P,−−sched−periodnanoseconds-
Specifies period parameter for SCHED_DEADLINE policy (Linux-specific).
−D,−−sched−deadlinenanoseconds-
Specifies deadline parameter for SCHED_DEADLINE policy (Linux-specific).
−R,−−reset−on−fork-
Add
SCHED_RESET_ON_FORKflag to theSCHED_FIFOorSCHED_RRscheduling policy (Linux-specific, supported since 2.6.31).
OPTIONS
−a, −−all−tasks-
Set or retrieve the scheduling attributes of all the tasks (threads) for a given PID.
−m, −−max-
Show minimum and maximum valid priorities, then exit.
−p, −−pid-
Operate on an existing PID and do not launch a new task.
−v, −−verbose-
Show status information.
−V, −−version-
Display version information and exit.
−h, −−help-
Display help text and exit.
USAGE
- The default behavior is to run a new command:
-
chrt
prioritycommand[arguments] - You can also retrieve the real-time attributes of an existing task:
-
chrt −p
pid - Or set them:
-
chrt −r −p priority pid
PERMISSIONS
A user must possess CAP_SYS_NICE to change the scheduling
attributes of a process. Any user can retrieve the scheduling
information.
NOTES
Only SCHED_FIFO,
SCHED_OTHER and SCHED_RR are part of POSIX 1003.1b Process
Scheduling. The other scheduling attributes may be ignored on
some systems.
Linux_zsingle_quotesz_ default scheduling policy is SCHED_OTHER.
SEE ALSO
nice(1), renice(1), taskset(1), sched(7)
See sched_setscheduler(2) for a description of the Linux scheduling scheme.
AVAILABILITY
The chrt command is part of the util-linux package and is available from https://www.kernel.org/pub/linux/utils/util-linux/.
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chrt(1) manpage Copyright (C) 2004 Robert Love Copyright (C) 2015 Karel Zak <kzakredhat.com> This is free documentation; you can redistribute it and/or modify it under the terms of the GNU General Public License, version 2, as published by the Free Software Foundation. The GNU General Public License_zsingle_quotesz_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 program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |