chrt

<html> <head> <title>chrt</title> <META NAME="KEYWORDS" CONTENT="chrt"> </head> <body BGCOLOR="#ffffff" LINK="#0000ff" VLINK="#0000ff" ALINK="#0000ff" TEXT="#000000"> <center> <h1>chrt</h1></center> <PRE> <A HREF="/man1/CHRT">CHRT(1)</A> User Commands <A HREF="/man1/CHRT">CHRT(1)</A> 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 exist- ing 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, sup- ported 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 <A HREF="/man7/sched">sched(7)</A> 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-spe- cific). -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 <A HREF="/man1/nice">nice(1)</A>, <A HREF="/man1/renice">renice(1)</A>, <A HREF="/man1/taskset">taskset(1)</A>, <A HREF="/man7/sched">sched(7)</A> See <A HREF="/man2/sched_setscheduler">sched_setscheduler(2)</A> 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 <A HREF="/man1/CHRT">CHRT(1)</A></PRE> <center> <h6>Man Pages Copyright Respective Owners. Site Copyright (C) 1994 - 2025 <a href="http://www.he.net">Hurricane Electric</a>. All Rights Reserved.</h6></center> </body> </html>

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