Chapter 36. Setting the priority for a process with the chrt utility

You can set the priority for a process using the chrt utility.

Prerequisites

  • You have administrator privileges.

36.1. Setting the process priority using the chrt utility

The chrt utility checks and adjusts scheduler policies and priorities. It can start new processes with the desired properties, or change the properties of a running process.

Procedure

  • To set the scheduling policy of a process, run the chrt command with the appropriate command options and parameters. In the following example, the process ID affected by the command is 1000, and the priority (-p) is 50. 

    # chrt -f -p 50 1000

    To start an application with a specified scheduling policy and priority, add the name of the application, and the path to it, if necessary, along with the attributes. 

    # chrt -r -p 50 /bin/my-app

    For more information on the chrt utility options, see The chrt utility options.

36.2. The chrt utility options

The chrt utility options include command options and parameters specifying the process and priority for the command.

Policy options

-f
Sets the scheduler policy to SCHED_FIFO.
-o
Sets the scheduler policy to SCHED_OTHER.
-r
Sets the scheduler policy to SCHED_RR (round robin).
-d
Sets the scheduler policy to SCHED_DEADLINE.
-p n

Sets the priority of the process to n.

When setting a process to SCHED_DEADLINE, you must specify the runtime, deadline, and period parameters.

For example: 

# chrt -d --sched-runtime 5000000 --sched-deadline 10000000 --sched-period 16666666 0 video_processing_tool

where

  • --sched-runtime 5000000 is the run time in nanoseconds.
  • --sched-deadline 10000000 is the relative deadline in nanoseconds.
  • --sched-period 16666666 is the period in nanoseconds.
  • 0 is a placeholder for unused priority required by the chrt command.

36.3. Additional resources

  • chrt(1) man page