User Tools

Site Tools


realtime:documentation:start

This is an old revision of the document!


Documentation

In order to fulfill the requirements of a real-time system, a system must react to an external event like an interrupt within a defined time frame. Therefore several mechanisms, configurations and implementation rules have to be considered.


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:

Publications

Several real-time related publications can help broaden your knowledge about real-time systems.

Known Limitations

Some functionality is not available on RT because its implementation is not compatible with RT. Those limitations can be true for everyone or it be architecture, platform or driver specific.

1)
Paul McKenney. A realtime preemption overview. https://lwn.net/Articles/146861/
realtime/documentation/start.1480689994.txt.gz · Last modified: 2016/12/02 14:46 by bigeasy