chrt(1) [linux man page]
CHRT(1) Linux User's Manual CHRT(1) NAME
chrt - manipulate real-time attributes of a process SYNOPSIS
chrt [options] prio command [arg]... chrt [options] -p [prio] pid DESCRIPTION
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 SCHED_OTHER, SCHED_FIFO, SCHED_RR, SCHED_BATCH, or SCHED_IDLE) and priority can be set and retrieved. The SCHED_BATCH policy is supported since Linux 2.6.16. The SCHED_IDLE policy is supported since Linux 2.6.23. The SCHED_RESET_ON_FORK flag for policies SCHED_RR and SCHED_FIFO is supported since Linux 2.6.31. OPTIONS
-p, --pid operate on an existing PID and do not launch a new task -b, --batch set scheduling policy to SCHED_BATCH (Linux specific) -f, --fifo set scheduling policy to SCHED_FIFO -i, --idle set scheduling policy to SCHED_IDLE (Linux specific) -m, --max show minimum and maximum valid priorities, then exit -o, --other set policy scheduling policy to SCHED_OTHER -r, --rr set scheduling policy to SCHED_RR (the default) -R, --reset-on-fork add SCHED_RESET_ON_FORK flag to the SCHED_FIFO or SCHED_RR scheduling policy (Linux specific) -v, --verbose show status information -h, --help display usage information and exit -V, --version display version information and exit USAGE
The default behavior is to run a new command:: chrt prio command [arguments] You can also retrieve the real-time attributes of an existing task: chrt -p pid Or set them: chrt -p prio 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. AUTHOR
Written by Robert M. Love. COPYRIGHT
Copyright (C) 2004 Robert M. Love This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICU- LAR PURPOSE. SEE ALSO
taskset(1), nice(1), renice(1) 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 ftp://ftp.kernel.org/pub/linux/utils/util-linux/. schedutils June 2010 CHRT(1)
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CHRT(1) User Commands CHRT(1) 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, the SCHED_RR is 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-deadline and --sched-period. The relation between the options required by the kernel is runtime <= deadline <= period. chrt copies period to deadline if --sched-deadline is not specified and deadline to runtime if --sched-runtime is not specified. It means that at least --sched-period has to be specified. See sched(7) for more details. SCHEDULING OPTIONS
-T, --sched-runtime nanoseconds Specifies runtime parameter for SCHED_DEADLINE policy (Linux-specific). -P, --sched-period nanoseconds Specifies period parameter for SCHED_DEADLINE policy (Linux-specific). -D, --sched-deadline nanoseconds Specifies deadline parameter for SCHED_DEADLINE policy (Linux-specific). -R, --reset-on-fork Add SCHED_RESET_ON_FORK flag to the SCHED_FIFO or SCHED_RR scheduling 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 priority command [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' 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. AUTHORS
Robert Love <rml@tech9.net> Karel Zak <kzak@redhat.com> AVAILABILITY
The chrt command is part of the util-linux package and is available from https://www.kernel.org/pub/linux/utils/util-linux/. util-linux January 2016 CHRT(1)