Hard Real-Time Linux for Off-The-Shelf Multicore Architectures

This document describes the research results that were obtained from the development of a real-time extension for the Linux operating system. The paper describes a full extension of the kernel, which enables hard real-time performance on a 64-bit x86 architecture. In the first part of this study, real-time systems are categorized and concepts of real-time operating systems are introduced to the reader. In addition, numerous well-known real-time operating systems are considered. QNX Neutrino, RT_PREEMPT Linux Patch and HLRT Linux Patch are analyzed in detail. The core concepts of these systems are shown and discussed. Furthermore, a test suite is developed, which is used to obtain expressive benchmarks from the systems that were analyzed before. The systems are evaluated on the basis of these benchmarks and compared to the real-time extension which is developed in this work. A requirements catalogue is defined based on the analysis of the stated operating systems. The design of a real-time extension is developed based on the specification catalogue and the identified core concepts. Furthermore, the concrete implementation of the developed real-time extension is presented in detail. Finally, the benchmarks of all analyzed systems, including the developed real-time extension, are compared to each other and evaluated

Real-Time Performance and Middleware on Multicore Linux Platforms

An increasing number of distributed real-time applications are running on multicore platforms. However, existing real-time middleware (e.g., Real-Time CORBA) lacks support for scheduling soft real-time tasks on multicore platforms while guaranteeing their time constraints will be satisfied. This paper makes three contributions to the state of the art in real-time system software for multicore platforms. First, it offers what is to our knowledge the first experimental analysis of real-time performance for vanilla Linux primitives on multicore platforms. Second, it presents MC-ORB, the first real-time object request broker (ORB), designed to exploit the features of multicore platforms, with admission control and task allocation services that can provide schedulability guarantees for soft real-time tasks on multicore platforms. Third, it gives a performance evaluation of MC-ORB on a Linux multicore testbed, the results of which demonstrate the efficiency and effectiveness of MC-ORB

Porting of the 802.15.4 stack on FreeRTOS in Asymmetric Multi Processing contexts for IoT solutions

L'obiettivo di questa tesi è effettuare il porting dello stack IEEE 802.15.4, che era già stato sviluppato per il sistema operativo Erika EE, all'interno di un ambiente FreeRTOS. Il tutto viene eseguito in un contesto di Asymmetric Multi Processing, al fine di delegare la gestione di reti IoT real-time a processori dedicati, mentre quello principale può occuparsi della gestione di tutte le altre periferiche