Technical Basics

Currently running tasks with low priority must be preempted to allow the real-time critical task to run. Preemption depends on the rules of the task’s scheduling policy. Another important aspect in a real-time system is the guaranteeing the exclusive use of certain resources for real-time tasks.

Technical details of PREEMPT_RT patch

The main aim of the PREEMPT_RT patch is to minimize the amount of kernel code that is non-preemptible ¹⁾. Therefore several substitution mechanisms and new mechanisms are implemented.

HOWTOs

There are three categories of HOWTOs:

• RTOS and RT application

• RT latency debugging

• RT tools and utilities

Publications

Several real-time related publications can help broaden your knowledge about real-time systems. Regarding PREEMPT_RT, a recent survey of available scientific works have been published (open access link).

Known Limitations

Some functionality is not available on RT because its implementation is not compatible with RT. Those limitations may apply to the to the kernel as a whole or may apply to specific architecture or platforms.