{ "mode": "man", "parameter": "chrt", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/chrt/1/json", "generated": "2026-06-03T03:32:48Z", "synopsis": "chrt [options] priority command argument ...\nchrt [options] -p [priority] PID", "sections": { "NAME": { "content": "chrt - manipulate the real-time attributes of a process\n", "subsections": [] }, "SYNOPSIS": { "content": "chrt [options] priority command argument ...\n\nchrt [options] -p [priority] PID\n", "subsections": [] }, "DESCRIPTION": { "content": "chrt sets or retrieves the real-time scheduling attributes of an existing PID, or runs\ncommand with the given attributes.\n", "subsections": [] }, "POLICIES": { "content": "", "subsections": [ { "name": "-o --other", "content": "Set scheduling policy to SCHEDOTHER (time-sharing scheduling). This is the default Linux\nscheduling policy.\n", "flag": "-o", "long": "--other" }, { "name": "-f --fifo", "content": "Set scheduling policy to SCHEDFIFO (first in-first out).\n", "flag": "-f", "long": "--fifo" }, { "name": "-r --rr", "content": "Set scheduling policy to SCHEDRR (round-robin scheduling). When no policy is defined,\nthe SCHEDRR is used as the default.\n", "flag": "-r", "long": "--rr" }, { "name": "-b --batch", "content": "Set scheduling policy to SCHEDBATCH (scheduling batch processes). Linux-specific,\nsupported since 2.6.16. The priority argument has to be set to zero.\n", "flag": "-b", "long": "--batch" }, { "name": "-i --idle", "content": "Set scheduling policy to SCHEDIDLE (scheduling very low priority jobs). Linux-specific,\nsupported since 2.6.23. The priority argument has to be set to zero.\n", "flag": "-i", "long": "--idle" }, { "name": "-d --deadline", "content": "Set scheduling policy to SCHEDDEADLINE (sporadic task model deadline scheduling).\nLinux-specific, supported since 3.14. The priority argument has to be set to zero. See\nalso --sched-runtime, --sched-deadline and --sched-period. The relation between the\noptions required by the kernel is runtime ⇐ deadline ⇐ period. chrt copies period to\ndeadline if --sched-deadline is not specified and deadline to runtime if --sched-runtime\nis not specified. It means that at least --sched-period has to be specified. See sched(7)\nfor more details.\n", "flag": "-d", "long": "--deadline" } ] }, "SCHEDULING OPTIONS": { "content": "", "subsections": [ { "name": "-T --sched-runtime", "content": "Specifies runtime parameter for SCHEDDEADLINE policy (Linux-specific).\n", "flag": "-T", "long": "--sched-runtime" }, { "name": "-P --sched-period", "content": "Specifies period parameter for SCHEDDEADLINE policy (Linux-specific).\n", "flag": "-P", "long": "--sched-period" }, { "name": "-D --sched-deadline", "content": "Specifies deadline parameter for SCHEDDEADLINE policy (Linux-specific).\n", "flag": "-D", "long": "--sched-deadline" }, { "name": "-R --reset-on-fork", "content": "Use SCHEDRESETONFORK or SCHEDFLAGRESETONFORK flag. Linux-specific, supported since\n2.6.31.\n\nEach thread has a reset-on-fork scheduling flag. When this flag is set, children created by\nfork(2) do not inherit privileged scheduling policies. After the reset-on-fork flag has been\nenabled, it can be reset only if the thread has the CAPSYSNICE capability. This flag is\ndisabled in child processes created by fork(2).\n\nMore precisely, if the reset-on-fork flag is set, the following rules apply for subsequently\ncreated children:\n\n• If the calling thread has a scheduling policy of SCHEDFIFO or SCHEDRR, the policy is\nreset to SCHEDOTHER in child processes.\n\n• If the calling process has a negative nice value, the nice value is reset to zero in\nchild processes.\n", "flag": "-R", "long": "--reset-on-fork" } ] }, "OPTIONS": { "content": "", "subsections": [ { "name": "-a --all-tasks", "content": "Set or retrieve the scheduling attributes of all the tasks (threads) for a given PID.\n", "flag": "-a", "long": "--all-tasks" }, { "name": "-m --max", "content": "Show minimum and maximum valid priorities, then exit.\n", "flag": "-m", "long": "--max" }, { "name": "-p --pid", "content": "Operate on an existing PID and do not launch a new task.\n", "flag": "-p", "long": "--pid" }, { "name": "-v --verbose", "content": "Show status information.\n", "flag": "-v", "long": "--verbose" }, { "name": "-V --version", "content": "Display version information and exit.\n", "flag": "-V", "long": "--version" }, { "name": "-h --help", "content": "Display help text and exit.\n", "flag": "-h", "long": "--help" } ] }, "USAGE": { "content": "The default behavior is to run a new command:\nchrt priority command [arguments]\n\nYou can also retrieve the real-time attributes of an existing task:\nchrt -p PID\n\nOr set them:\nchrt -r -p priority PID\n", "subsections": [] }, "PERMISSIONS": { "content": "A user must possess CAPSYSNICE to change the scheduling attributes of a process. Any user\ncan retrieve the scheduling information.\n", "subsections": [] }, "NOTES": { "content": "Only SCHEDFIFO, SCHEDOTHER and SCHEDRR are part of POSIX 1003.1b Process Scheduling. The\nother scheduling attributes may be ignored on some systems.\n\nLinux' default scheduling policy is SCHEDOTHER.\n", "subsections": [] }, "AUTHORS": { "content": "Robert Love , Karel Zak \n", "subsections": [] }, "SEE ALSO": { "content": "nice(1), renice(1), taskset(1), sched(7)\n\nSee schedsetscheduler(2) for a description of the Linux scheduling scheme.\n", "subsections": [] }, "REPORTING BUGS": { "content": "For bug reports, use the issue tracker at https://github.com/karelzak/util-linux/issues.\n", "subsections": [] }, "AVAILABILITY": { "content": "The chrt command is part of the util-linux package which can be downloaded from Linux Kernel\nArchive .\n\n\n\nutil-linux 2.37.2 2021-06-02 CHRT(1)", "subsections": [] } }, "summary": "chrt - manipulate the real-time attributes of a process", "flags": [ { "flag": "-a", "long": "--all-tasks", "arg": null, "description": "Set or retrieve the scheduling attributes of all the tasks (threads) for a given PID." }, { "flag": "-m", "long": "--max", "arg": null, "description": "Show minimum and maximum valid priorities, then exit." }, { "flag": "-p", "long": "--pid", "arg": null, "description": "Operate on an existing PID and do not launch a new task." }, { "flag": "-v", "long": "--verbose", "arg": null, "description": "Show status information." }, { "flag": "-V", "long": "--version", "arg": null, "description": "Display version information and exit." }, { "flag": "-h", "long": "--help", "arg": null, "description": "Display help text and exit." } ], "examples": [], "see_also": [ { "name": "nice", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/nice/1/json" }, { "name": "renice", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/renice/1/json" }, { "name": "taskset", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/taskset/1/json" }, { "name": "sched", "section": "7", "url": "https://www.chedong.com/phpMan.php/man/sched/7/json" }, { "name": "schedsetscheduler", "section": "2", "url": "https://www.chedong.com/phpMan.php/man/schedsetscheduler/2/json" } ], "tldr": { "source": "official", "description": "Manipulate the real-time attributes of a process.", "examples": [ { "description": "Display attributes of a process", "command": "chrt {{-p|--pid}} {{pid}}" }, { "description": "Display attributes of all threads of a process", "command": "chrt {{-a|--all-tasks}} {{-p|--pid}} {{pid}}" }, { "description": "Display the min/max priority values that can be used with `chrt`", "command": "chrt {{-m|--max}}" }, { "description": "Set the scheduling priority of a process", "command": "chrt {{-p|--pid}} {{priority}} {{pid}}" }, { "description": "Set the scheduling policy of a process", "command": "chrt --{{deadline|idle|batch|rr|fifo|other}} {{-p|--pid}} {{priority}} {{pid}}" } ] } }