Interfacing to Time-Triggered Communication Systems

Time-triggered communication facilitates the construction of multi-component real-time systems whose components are in control of their temporal behavior. However, the interface of a time-triggered communication system has to be accessed with care, to avoid that the temporal independence of components gets lost. This paper shows two interfacing strategies, one for asynchronous interface access (in two variants, one being the new Rate-Bounded Non-Blocking Communication protocol) and one for time-aware, synchronized interface access, that allow components to maintain temporal independence. The paper describes and compares the interfacing strategies.Final Accepted Versio

Divide and Measure : CFG Segmentation for the Measurement-Based Analysis of Resource Consumption

A computer system is a good computer system if it correctly performs the task it was intended to perform. This is not even half of the truth: Non-functional requirements are abundant in the world of software and system engineering, even if they are not always stated explicitly. In our work we are concerned with the measurement-based analysis of resource consumption. Examples of resources are time, energy, or memory space. In the context of our measurement-based approach for software analysis, we face the problem of breaking the software under examination into smaller parts of managable size, a process dubbed CFG Segmentation

Ingredients for the specification of mixed-criticality real-time systems

Models for real-time computing are available with different timing requirements. With the ongoing trend towards integration of services of different degrees of timing strictness on one single platform, there is a need to specify computing models for such scenarios. In this paper we study the requirements to specify mixed criticality real-time systems (MCRTS). Mixed criticality systems have been studied intensively over the last years. Existing formulations of the scheduling problem for mixed criticality systems do not consider the different timing strictness requirements of the tasks. In this paper we argue that mixed criticality properties as well as real-time properties have to be considered together in order to provide the maximal utility of a system. Based on that argument we present a list of ingredients required for the specification of MCRTS. We outline conceptually, how a system can take advantage of having MCRTS specifications available. We present some examples to show the usefulness of specifying MCRTS properties for real-life systems.Final Accepted Versio

ATMP: An Adaptive Tolerance-based Mixed-criticality Protocol for Multi-core Systems

© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted ncomponent of this work in other works.The challenge of mixed-criticality scheduling is to keep tasks of higher criticality running in case of resource shortages caused by faults. Traditionally, mixedcriticality scheduling has focused on methods to handle faults where tasks overrun their optimistic worst-case execution time (WCET) estimate. In this paper we present the Adaptive Tolerance based Mixed-criticality Protocol (ATMP), which generalises the concept of mixed-criticality scheduling to handle also faults of other nature, like failure of cores in a multi-core system. ATMP is an adaptation method triggered by resource shortage at runtime. The first step of ATMP is to re-partition the task to the available cores and the second step is to optimise the utility at each core using the tolerance-based real-time computing model (TRTCM). The evaluation shows that the utility optimisation of ATMP can achieve a smoother degradation of service compared to just abandoning tasks

Influences on Throughput and Latency in Stream Programs

Vu Thien Nga Nguyen and Raimund Kirner, 'Influences on Throughput and Latency in Stream Programs' paper presented at the 2nd Workshop on Feedback-Directed Compiler Optimization for Multi-Core Architectures. Berlin, Germany. 22 January 2013Stream programming is a promising approach to execute programs on parallel hardware such as multi-core systems. It allows to reuse sequential code at component level and to extend such code with concurrency-handling at the communication level. In this paper we investigate in the performance of stream programs in terms of throughput and latency. We identify factors that affect these performance metrics and propose an efficient scheduling approach to obtain the maximal performance

On undecidability results of real programming languages

Original article can be found at : http://www.vmars.tuwien.ac.at/ Copyright Institut fur Technische InformatikOften, it is argued that some problems in data-flow analysis such as e.g. worst case execution time analysis are undecidable (because the halting problem is) and therefore only a conservative approximation of the desired information is possible. In this paper, we show that the semantics for some important real programming languages – in particular those used for programming embedded devices – can be modeled as finite state systems or pushdown machines. This implies that the halting problem becomes decidable and therefore invalidates popular arguments for using conservative analysis

Development of a framework for automated systematic testing of safety-critical embedded systems

“This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder." “Copyright IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.”In this paper we introduce the development of a framework for testing safety-critical embedded systems based on the concepts of model-based testing. In model-based testing the test cases are derived from a model of the system under test. In our approach the model is an automaton model that is automatically extracted from the C-source code of the system under test. Beside random test data generation the test case generation uses formal methods, in detail model checking techniques. To find appropriate test cases we use the requirements defined in the system specification. To cover further execution paths we developed an additional, to our best knowledge, novel method based on special structural coverage criteria. We present preliminary results on the model extraction using a concrete industrial case study from the automotive domain

Interfaces and Concepts to Build Large Resilient and Predictable Systems

© 2020 The Author(s). This an open access work distributed under the terms of the Creative Commons Attribution Licence (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.Progress in technology not only results in tools of improved capabilities, but also pushes towards integration to create larger systems with unprecedented capabilities. Building such systems with safety-relevant services demands appropriate system interfaces and algorithmic concepts. In this paper we list examples of ingredients to build large resilient and predictable systems.Peer reviewe

Asynchronous vs. Synchronous Interfacing to Time-Triggered Communication Systems

© 2019 Published by Elsevier B.V. This manuscript is made available under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International licence (CC BY-NC-ND 4.0). For further details please see: https://creativecommons.org/licenses/by-nc-nd/4.0/Time-triggered communication facilitates the construction of multi-component real-time systems whose components are in control of their temporal behaviour. However, the interface of a time-triggered communication system has to be accessed with care, to avoid that the temporal independence of components gets lost. This paper shows two interfacing strategies, one for asynchronous interface access (in two variants, one being the new Rate-bounded Non-Blocking Communication protocol) and one for time-aware, synchronized interface access, that allow components to maintain temporal independence. The paper describes and compares these interfacing strategies.Peer reviewe