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
       Karel Zak

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)