A Survey of Timing Verification Techniques for Multi-Core Real-Time Systems

This survey provides an overview of the scientific literature on timing verification techniques for multi-core real-time systems. It reviews the key results in the field from its origins around 2006 to the latest research published up to the end of 2018. The survey highlights the key issues involved in providing guarantees of timing correctness for multi-core systems. A detailed review is provided covering four main categories: full integration, temporal isolation, integrating interference effects into schedulability analysis, and mapping and allocation. The survey concludes with a discussion of the advantages and disadvantages of these different approaches, identifying open issues, key challenges, and possible directions for future research

Hierarchical Transactions for Hardware/Software Cosynthesis

Modern heterogeneous devices provide of a variety of computationally diverse components holding tremendous performance and power capability. Hardware-software cosynthesis offers system-level synthesis and optimization opportunities to realize the potential of these evolving architectures. Efficiently coordinating high-throughput data to make use of available computational resources requires a myriad of distributed local memories, caching structures, and data motion resources. In fact, storage, caching, and data transfer components comprise the majority of silicon real estate. Conventional automated approaches, unfortunately, do not effectively represent applications in a way that captures data motion and state management which dictate dominant system costs. Consequently, existing cosynthesis methods suffer from poor utility of computational resources. Automated cosynthesis tailored towards memory-centric optimizations can address the challenge, adapting partitioning, scheduling, mapping, and binding techniques to maximize overall system utility.This research presents a novel hierarchical transaction model that formalizes state and control management through an abstract data/control encapsulation semantic. It is designed from the ground-up to enable efficient synthesis across heterogeneous system components, with an emphasis on memory capacity constraints. It intrinsically encourages a high degree of concurrency and latency tolerance, and provides verification tools to ensure correctness. A unique data/execution hierarchical encapsulation framework guarantees scalable analysis, supporting a novel concept of state and control mobility. A front-end language allows concise expression of designer intent, and is structured with synthesis in mind. Designers express families of valid executions in a minimal format through high-level dependencies, type systems, and computational relationships, allowing synthesis tools to manage lower-level details. This dissertation introduces and exercises the model, discussing language construction, demonstrating control and data-dominated applications, and presenting a synthesis path that exhibits near-linear scalability with problem size

Many-core architectures with time predictable execution Support for hard real-time applications

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (p. 183-193).Hybrid control systems are a growing domain of application. They are pervasive and their complexity is increasing rapidly. Distributed control systems for future "Intelligent Grid" and renewable energy generation systems are demanding high-performance, hard real-time computation, and more programmability. General-purpose computer systems are primarily designed to process data and not to interact with physical processes as required by these systems. Generic general-purpose architectures even with the use of real-time operating systems fail to meet the hard realtime constraints of hybrid system dynamics. ASIC, FPGA, or traditional embedded design approaches to these systems often result in expensive, complicated systems that are hard to program, reuse, or maintain. In this thesis, we propose a domain-specific architecture template targeting hybrid control system applications. Using power electronics control applications, we present new modeling techniques, synthesis methodologies, and a parameterizable computer architecture for these large distributed control systems. We propose a new system modeling approach, called Adaptive Hybrid Automaton, based on previous work in control system theory, that uses a mixed-model abstractions and lends itself well to digital processing. We develop a domain-specific architecture based on this modeling that uses heterogeneous processing units and predictable execution, called MARTHA. We develop a hard real-time aware router architecture to enable deterministic on-chip interconnect network communication. We present several algorithms for scheduling task-based applications onto these types of heterogeneous architectures. We create Heracles, an open-source, functional, parameterized, synthesizable many-core system design toolkit, that can be used to explore future multi/many-core processors with different topologies, routing schemes, processing elements or cores, and memory system organizations. Using the Heracles design tool we build a prototype of the proposed architecture using a state-of-the-art FPGA-based platform, and deploy and test it in actual physical power electronics systems. We develop and release an open-source, small representative set of power electronics system applications that can be used for hard real-time application benchmarking.by Michel A. Kinsy.Ph.D

Schedulability, Response Time Analysis and New Models of P-FRP Systems

Functional Reactive Programming (FRP) is a declarative approach for modeling and building reactive systems. FRP has been shown to be an expressive formalism for building applications of computer graphics, computer vision, robotics, etc. Priority-based FRP (P-FRP) is a formalism that allows preemption of executing programs and guarantees real-time response. Since functional programs cannot maintain state and mutable data, changes made by programs that are preempted have to be rolled back. Hence in P-FRP, a higher priority task can preempt the execution of a lower priority task, but the preempted lower priority task will have to restart after the higher priority task has completed execution. This execution paradigm is called Abort-and-Restart (AR). Current real-time research is focused on preemptive of non-preemptive models of execution and several state-of-the-art methods have been developed to analyze the real-time guarantees of these models. Unfortunately, due to its transactional nature where preempted tasks are aborted and have to restart, the execution semantics of P-FRP does not fit into the standard definitions of preemptive or non-preemptive execution, and the research on the standard preemptive and non-preemptive may not applicable for the P-FRP AR model. Out of many research areas that P-FRP may demands, we focus on task scheduling which includes task and system modeling, priority assignment, schedulability analysis, response time analysis, improved P-FRP AR models, algorithms and corresponding software. In this work, we review existing results on P-FRP task scheduling and then present our research contributions: (1) a tighter feasibility test interval regarding the task release offsets as well as a linked list based algorithm and implementation for scheduling simulation; (2) P-FRP with software transactional memory-lazy conflict detection (STM-LCD); (3) a non-work-conserving scheduling model called Deferred Start; (4) a multi-mode P-FRP task model; (5) SimSo-PFRP, the P-FRP extension of SimSo - a SimPy-based, highly extensible and user friendly task generator and task scheduling simulator.Computer Science, Department o

TANGO: Transparent heterogeneous hardware Architecture deployment for eNergy Gain in Operation

The paper is concerned with the issue of how software systems actually use Heterogeneous Parallel Architectures (HPAs), with the goal of optimizing power consumption on these resources. It argues the need for novel methods and tools to support software developers aiming to optimise power consumption resulting from designing, developing, deploying and running software on HPAs, while maintaining other quality aspects of software to adequate and agreed levels. To do so, a reference architecture to support energy efficiency at application construction, deployment, and operation is discussed, as well as its implementation and evaluation plans.Comment: Part of the Program Transformation for Programmability in Heterogeneous Architectures (PROHA) workshop, Barcelona, Spain, 12th March 2016, 7 pages, LaTeX, 3 PNG figure

Embedded System Design

A unique feature of this open access textbook is to provide a comprehensive introduction to the fundamental knowledge in embedded systems, with applications in cyber-physical systems and the Internet of things. It starts with an introduction to the field and a survey of specification models and languages for embedded and cyber-physical systems. It provides a brief overview of hardware devices used for such systems and presents the essentials of system software for embedded systems, including real-time operating systems. The author also discusses evaluation and validation techniques for embedded systems and provides an overview of techniques for mapping applications to execution platforms, including multi-core platforms. Embedded systems have to operate under tight constraints and, hence, the book also contains a selected set of optimization techniques, including software optimization techniques. The book closes with a brief survey on testing. This fourth edition has been updated and revised to reflect new trends and technologies, such as the importance of cyber-physical systems (CPS) and the Internet of things (IoT), the evolution of single-core processors to multi-core processors, and the increased importance of energy efficiency and thermal issues

Embedded System Design

A unique feature of this open access textbook is to provide a comprehensive introduction to the fundamental knowledge in embedded systems, with applications in cyber-physical systems and the Internet of things. It starts with an introduction to the field and a survey of specification models and languages for embedded and cyber-physical systems. It provides a brief overview of hardware devices used for such systems and presents the essentials of system software for embedded systems, including real-time operating systems. The author also discusses evaluation and validation techniques for embedded systems and provides an overview of techniques for mapping applications to execution platforms, including multi-core platforms. Embedded systems have to operate under tight constraints and, hence, the book also contains a selected set of optimization techniques, including software optimization techniques. The book closes with a brief survey on testing. This fourth edition has been updated and revised to reflect new trends and technologies, such as the importance of cyber-physical systems (CPS) and the Internet of things (IoT), the evolution of single-core processors to multi-core processors, and the increased importance of energy efficiency and thermal issues

System-level design of energy-efficient sensor-based human activity recognition systems: a model-based approach

This thesis contributes an evaluation of state-of-the-art dataflow models of computation regarding their suitability for a model-based design and analysis of human activity recognition systems, in terms of expressiveness and analyzability, as well as model accuracy. Different aspects of state-of-the-art human activity recognition systems have been modeled and analyzed. Based on existing methods, novel analysis approaches have been developed to acquire extra-functional properties like processor utilization, data communication rates, and finally energy consumption of the system

Future of Functional Reactive Programming in Real-Time Systems

The evolution of programming paradigms and the development of new programming languages are driven by the needs of problem domains. Functional reactive programming (FRP) combines functional programming (FP) and reactive programming (RP) concepts that leverage asynchronous dataflow from reactive programming and higher-level abstractions building blocks from functional programming to enable developers to define data flows and transformations declaratively. Declarative programming allows developers to concentrate more on the problem to be solved rather than the implementation details, resulting in efficient and concise code. Over the years, various FRP designs have been proposed in real-time application areas. Still, it remains unclear how FRP-based solutions compare with traditional methods for implementing these applications. In this survey, we studied the usefulness of FRP in some real-time applications, such as game development, animation, graphical user interface(GUI), and embedded system. We conducted a qualitative comparison for game development and studied various applications in animation, GUI, and embedded systems. We found that using FRP in these applications is quite difficult because of insufficient libraries and tools. Additionally, due to high learning curves and a need for experienced developers, the development process in FRP takes time and effort. Our examination of two well-known games: Asteroid and Pong, in three programming paradigms: imperative programming using the Unity game engine, FP in Haskell, and FRP in the Yampa library, showed that imperative programming is effective in terms of performance and usability. The other two paradigms for developing games from scratch are inefficient and challenging. Despite the fact that FRP was designed for animation, the majority of its applications are underperforming. FRP is more successful for GUI applications, where libraries like RxJS have been used in many web interfaces. FRP is also applied in developing embedded system applications for its effective memory management, maintainability, and predictability. Developing efficient solutions from scratch is not suitable in FRP due to several factors, such as poor performance compared to other programming paradigms, programming complexity, and a steep learning curve. Instead, developers can be benefited from utilizing FRP-supported modular platforms to build robust and scalable real-time applications