1,352,622 research outputs found

    Run-time monitoring in real-time operating systems

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    Embedded systems are increasingly complex and dynamic, imposing progressively higher developing time and costs. Tuning a particular system for deployment is thus becoming more demanding. Furthermore when considering systems which have to adapt themselves to evolving requirements and changing service requests. In this perspective, run-time monitoring of the system behaviour becomes an important requirement, allowing to dynamically capturing the actual scheduling progress and resource utilization. For this to succeed, operating systems need to expose their internal behaviour and state, making it available to external applications, and a runtime monitoring mechanism must be available. However, such mechanism can impose a burden in the system itself if not wisely used. In this paper we explore this problem and propose a framework, which is intended to provide this run-time mechanism whilst achieving code separation, run-time efficiency and flexibility for the final developer

    Towards an HLA Run-time Infrastructure with Hard Real-time Capabilities

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    Our work takes place in the context of the HLA standard and its application in real-time systems context. The HLA standard is inadequate for taking into consideration the different constraints involved in real-time computer systems. Many works have been invested in order to providing real-time capabilities to Run Time Infrastructures (RTI) to run real time simulation. Most of these initiatives focus on major issues including QoS guarantee, Worst Case Transit Time (WCTT) knowledge and scheduling services provided by the underlying operating systems. Even if our ultimate objective is to achieve real-time capabilities for distributed HLA federations executions, this paper describes a preliminary work focusing on achieving hard real-time properties for HLA federations running on a single computer under Linux operating systems. Our paper proposes a novel global bottom up approach for designing real-time Run time Infrastructures and a formal model for validation of uni processor to (then) distributed real-time simulation with CERTI

    A comprehensive approach in performance evaluation for modernreal-time operating systems

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    In real-time computing the accurate characterization of the performance and determinism that a particular real-time operating system/hardware combination can provide for real-time applications is essential. This issue is not properly addressed by existing performance metrics mainly due to the lack of completeness and generalization. In this paper we present a set of comprehensive, easy-to-implement and useful metrics covering three basic real-time operating system features: response to external events, intertask synchronization and resource sharing, and intertask data transferring. The evaluation of real-time operating systems using a set of fine-grained metrics is fundamental to guarantee that we can reach the required determinism in real-world applications.Publicad

    Time-critical multirate scheduling using contemporary real-time operating system services

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    Although real-time operating systems provide many of the task control services necessary to process time-critical applications (i.e., applications with fixed, invariant deadlines), it may still be necessary to provide a scheduling algorithm at a level above the operating system in order to coordinate a set of synchronized, time-critical tasks executing at different cyclic rates. The scheduling requirements for such applications and develops scheduling algorithms using services provided by contemporary real-time operating systems

    Toward the hardening of real-time operating systems

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    Safety and Mission-critical systems are evolving daily, requiring increasing levels of complexity in their design. While bare-metal single CPU systems were dedicated to such systems in the past, nowadays, multicore CPUs, GPUs, and other accelerators require more complex software management, with the need for an operating system controlling everything. The presence of the operating system opens more challenges to securing the final system’s full dependability. This paper analyses the hardening scenarios based on the evidence gathered by selective fault injection analysis of Real-Time Operating systems. While solutions might be delivered in different fashions, the emphasis on the paper is on the right approach to spot the sensitive part of the Operating system, saving the design from massive overheads

    PERTS: A Prototyping Environment for Real-Time Systems

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    PERTS is a prototyping environment for real-time systems. It is being built incrementally and will contain basic building blocks of operating systems for time-critical applications, tools, and performance models for the analysis, evaluation and measurement of real-time systems and a simulation/emulation environment. It is designed to support the use and evaluation of new design approaches, experimentations with alternative system building blocks, and the analysis and performance profiling of prototype real-time systems

    Real-Time Operating Systems and Programming Languages for Embedded Systems

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    In this chapter, we present the different alternatives that are available today for the development of real-time embedded systems. In particular, we will focus on the programming languages use like C++, Java and Ada and the operating systems like Linux-RT, FreeRTOS, TinyOS, etc. In particular we will analyze the actual state of the art for developing embedded systems under the WORA paradigm with standard Java [1], its Real-Time Specification and with the use of Real-Time Core Extensions and pico Java based CPUs [5]. We expect the reader to have a clear view of the opportunities present at the moment of starting a design with its pros and cons so it can choose the best one to fit its case.Fil: Orozco, Javier Dario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Laboratorio de Sistemas Digitales; ArgentinaFil: Santos, Rodrigo Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Laboratorio de Sistemas Digitales; Argentin

    A Novel Side-Channel in Real-Time Schedulers

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    We demonstrate the presence of a novel scheduler side-channel in preemptive, fixed-priority real-time systems (RTS); examples of such systems can be found in automotive systems, avionic systems, power plants and industrial control systems among others. This side-channel can leak important timing information such as the future arrival times of real-time tasks.This information can then be used to launch devastating attacks, two of which are demonstrated here (on real hardware platforms). Note that it is not easy to capture this timing information due to runtime variations in the schedules, the presence of multiple other tasks in the system and the typical constraints (e.g., deadlines) in the design of RTS. Our ScheduLeak algorithms demonstrate how to effectively exploit this side-channel. A complete implementation is presented on real operating systems (in Real-time Linux and FreeRTOS). Timing information leaked by ScheduLeak can significantly aid other, more advanced, attacks in better accomplishing their goals

    Stress Injection Study on Hard Real-Time Operating Systems

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    The automotive software complexity has increased exponentially in the last 30 years. Nowadays, automotive applications are built on top of hard real-time operating system where many tasks are executed. Due to the automotive high integration levels and the time-to-market, software integration and robustness tests should be performed effectively and efficiently. Infineon Technologies for the AURIX 2G microcontroller has integrated a novel hardware architecture to support the Resource Usage Test and the Stress Test. Despite this hardware support, it has never been used before. Then, it is critical to propose a method to efficiently use this structure and to allow the evaluation of the performance and reliability of the chips. This thesis develops a method and a tool that uses stress injection to analyze the performance, robustness values and boundaries of hard real-time systems under different scenarios. The designer is able: i) to configure the embedded debugging hardware architecture to efficiently explore different stress scenarios; ii) to gather information; and to quantify different types of performance and robustness metrics. The method is automated and fully parameterizable. The developed tool in this thesis is called Galenus, it is integrated into the already existing internal debugging environment of Infineon Technologies for the AURIX microcontroller. The stress injection is based on the reduction of the effective performance of a SoC component (e.g., TriCore within AURIX). The stress injection allows to assess the sensitivity of the SoC under different stress scenarios. These scenarios are defined on the offline initial state using formal methods of scheduling theory. Using the stress injection method, the SoC designer can identify possible risk scenarios testing the performance and robustness of the system at runtime. This thesis is based on the stress injection by CPU suspension within two types of software application, RTOS and Bare-metal
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