манипулировать атрибутами процесса в реальном времени (manipulate the real-time attributes of a process)
Имя (Name)
chrt - manipulate the real-time attributes of a process
Синопсис (Synopsis)
chrt [options] priority command argument ...
chrt [options] -p [priority] PID
Описание (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 (time-sharing
scheduling). This is the default Linux scheduling policy.
-f, --fifo
Set scheduling policy to SCHED_FIFO (first in-first out).
-r, --rr
Set scheduling policy to SCHED_RR (round-robin scheduling).
When no policy is defined, the SCHED_RR is used as the
default.
-b, --batch
Set scheduling policy to SCHED_BATCH (scheduling batch
processes). Linux-specific, supported since 2.6.16. The
priority argument has to be set to zero.
-i, --idle
Set scheduling policy to SCHED_IDLE (scheduling very low
priority jobs). Linux-specific, supported since 2.6.23. The
priority argument has to be set to zero.
-d, --deadline
Set scheduling policy to SCHED_DEADLINE (sporadic task model
deadline scheduling). 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
Use SCHED_RESET_ON_FORK or SCHED_FLAG_RESET_ON_FORK flag.
Linux-specific, supported since 2.6.31.
Each thread has a reset-on-fork scheduling flag. When this flag
is set, children created by fork(2) do not inherit privileged
scheduling policies. After the reset-on-fork flag has been
enabled, it can be reset only if the thread has the CAP_SYS_NICE
capability. This flag is disabled in child processes created by
fork(2).
More precisely, if the reset-on-fork flag is set, the following
rules apply for subsequently created children:
• If the calling thread has a scheduling policy of SCHED_FIFO
or SCHED_RR, the policy is reset to SCHED_OTHER in child
processes.
• If the calling process has a negative nice value, the nice
value is reset to zero in child processes.
Параметры (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.
Использование (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
Разрешения (Permissions)
A user must possess CAP_SYS_NICE to change the scheduling
attributes of a process. Any user can retrieve the scheduling
information.
Примечание (Note)
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.
