Optimizing Linux with chrt Mastering Process Scheduling

Unlock the Power of Real-Time Scheduling in Linux for Enhanced System Performance

Luca Berton



The chrt command in Linux is a powerful tool designed for manipulating the real-time attributes of a process. This command allows users to set or retrieve the real-time scheduling attributes of an existing process identified by its PID (Process ID), or to execute a command with specified scheduling attributes. Understanding how to use chrt effectively can significantly enhance system performance and responsiveness, especially in environments where real-time processing is critical. Below, we delve into the syntax, options, and practical examples to help you master the chrt command.


The basic syntax of the chrt command is as follows:

  • To set scheduling attributes for a command:
$ chrt [options] priority command [argument ...]
  • To set or get the scheduling attributes for an existing process:
$ chrt [options] -p [priority] pid

Policy Options

chrt offers several policy options to define the scheduling policy:

  • -b, --batch: Sets the policy to SCHED_BATCH, optimized for batch processing.
  • -d, --deadline: Sets the policy to SCHED_DEADLINE, for tasks with strict timing requirements.
  • -f, --fifo: Sets the policy to SCHED_FIFO, implementing a first-in, first-out scheduling.
  • -i, --idle: Sets the policy to SCHED_IDLE, for very low priority jobs.
  • -o, --other: Sets the policy to SCHED_OTHER, the default Linux time-sharing scheduling.
  • -r, --rr: Sets the policy to SCHED_RR, a round-robin scheduling.

Scheduling Options

  • SCHED_BATCH: Optimizes for batch processing without the need for immediate interaction.
  • SCHED_FIFO: A non-preemptive, first-in, first-out scheduling, ideal for batch systems.
  • SCHED_IDLE: Suitable for running very low priority background jobs.



Luca Berton

I help creative Automation DevOps, Cloud Engineer, System Administrator, and IT Professional to succeed with Ansible Technology to automate more things everyday