A Hardware Time Manager Implementation for the Xenomai Real-Time Kernel of Embedded Linux

TL;DR

This paper introduces a hardware-based time management solution for the Xenomai real-time kernel in embedded Linux, aiming to improve timing precision and reduce CPU overhead by offloading time management to an FPGA-based hardware component.

Contribution

It presents a novel hardware implementation of the time manager for Xenomai, significantly reducing overhead and enhancing real-time performance in embedded Linux systems.

Findings

Hardware time manager reduces CPU load

Improves timing precision of Xenomai

Enhances real-time determinism

Abstract

Nowadays, the use of embedded operating systems in different embedded projects is subject to a tremendous growth. Embedded Linux is becoming one of those most popular EOSs due to its modularity, efficiency, reliability, and cost. One way to make it hard real-time is to include a real-time kernel like Xenomai. One of the key characteristics of a Real-Time Operating System (RTOS) is its ability to meet execution time deadlines deterministically. So, the more precise and flexible the time management can be, the better it can handle efficiently the determinism for different embedded applications. RTOS time precision is characterized by a specific periodic interrupt service controlled by a software time manager. The smaller the period of the interrupt, the better the precision of the RTOS, the more it overloads the CPU, and though reduces the overall efficiency of the RTOS. In this paper, we propose to drastically reduce these overheads by migrating the time management service of Xenomai into a configurable hardware component to relieve the CPU. The hardware component is implemented in a Field Programmable Gate Array coupled to the CPU. This work was achieved in a Master degree project where students could apprehend many fields of embedded systems: RTOS programming, hardware design, performance evaluation, etc.