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/.