Download or read book Resource Access Control in RT Linux and Energy aware Real time Scheduling written by Guang Xie and published by . This book was released on 2003 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: General-purpose operating systems, like Linux, Windows NT, optimize average performance and try to give every process a fair share of compute time. But the goal of real-time operating system (RTOS) is to guarantee precise timing and predictable performance rather than average performance. Nowadays several RTOS are being developed by different research groups to make the free Linux a viable platform to support real-time requirements while retaining its general-purpose features. But the existing RT-Linux versions provide limited resource access control support, which is necessary to prevent priority inversion and deadlock. In this thesis, we modify FSMLabs' RTLinux, which provides a loadable scheduler for fixed priority-driven scheduler, to accommodate two popular resource access control protocols, namely, Priority Inheritance and Priority Ceiling Protocols. We make suitable modifications in APIs to support these protocols while still maintaining backward compatibility. A last-in-first-out (LIFO) queue is introduced to simplify the implementation of Priority Ceiling Protocol. We have also developed a graphical simulation tool of the schedulers. Finally, we use several examples to test and verify the implementation. Power efficiency is a very important aspect in embedded systems, many of which have real-time requirements. Based on the characteristic of the prevailing CMOS process, Real-time Dynamic Voltage Scaling (RT-DVS) can dramatically reduce the energy dissipation by dynamically lowering the supply voltage and execution frequency, while still meeting tasks' deadlines. By carefully studying the behavior of the optimal execution curve of the stochastic execution time task set, we propose a new RT-DVS algorithm, which can acquire a near-optimal performance and when the variance of computation time of tasks approaches zero, the average energy dissipation converges to the optimum.

Download or read book Energy aware Operating System Design written by Padmanabhan Pillai and published by . This book was released on 2004 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Energy aware Real time Scheduling on Heterogeneous and Homogeneous Platforms in the Era of Parallel Computing written by Ashik Ahmed Bhuiyan and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Multi-core processors increasingly appear as an enabling platform for embedded systems, e.g., mobile phones, tablets, computerized numerical controls, etc. The parallel task model, where a task can execute on multiple cores simultaneously, can efficiently exploit the multi-core platform’s computational ability. Many computation-intensive systems (e.g., self-driving cars) that demand stringent timing requirements often evolve in the form of parallel tasks. Several real-time embedded system applications demand predictable timing behavior and satisfy other system constraints, such as energy consumption.

Download or read book Energy Aware Scheduling for Real Time Embedded Systems written by Muhammad Khurram Bhatti and published by LAP Lambert Academic Publishing. This book was released on 2012-04 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: Real-time embedded systems have become ubiquitous in our daily life. Due to their diversified usage, the research on these systems has confronted with many emerging challenges. One such challenge is to reduce power and energy consumption while maintaining assurance that timing constraints will be met. Power densities in microprocessors are almost doubled every three years. As energy is power integrated over time, supplying the required energy may become prohibitively expensive, or even technologically infeasible. This is particularly difficult in portable systems that heavily rely on batteries for energy, and will become even more critical as battery capacities are increasing at a much slower rate than power consumption. This book presents four contributions that are based on the thesis that energy-efficiency of Real-time Embedded Systems and scheduling are closely related problems and therefore, should be tackled together for optimal results. Contributions of this book are: 1) Two-level Hierarchical Scheduling Algorithm for Multiprocessor Systems, 2) Assertive Dynamic Power Management Scheme, 3) Deterministic Stretch-to-Fit DVFS Technique, and 4) Hybrid Power Management Scheme.

Download or read book Real Time Task Scheduling for Energy Aware Embedded Systems written by and published by . This book was released on 2005 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a new approach for scheduling workloads containing periodic tasks in real-time systems. The proposed approach minimizes the total energy consumed by the task set and guarantees that the deadline for every periodic task is met. As embedded software becomes a larger component of system-on-a-chip design, energy management using the operating system becomes increasingly important. We present a mixed-integer linear programming model for the NP-complete scheduling problem and solve it for moderate-sized problem instances using a public-domain solver. For larger task sets, we present a novel low-energy earliest-deadline-first (LEDF) scheduling algorithm and apply it to two real-life task sets.

Download or read book Power and Thermal Aware Scheduling for Real time Computing Systems written by Huang Huang and published by LAP Lambert Academic Publishing. This book was released on 2013 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have been enjoying tremendous benefits thanks to the revolutionary advancement of computing systems, driven by the remarkable semiconductor technology scaling and the advanced processor architecture. However, the exponentially increased transistor density has directly led to increased power consumption and elevated system temperature. The power and thermal issues have posed enormous challenges and threaten to slow down the continuous evolvement of computer technology. Effective power/thermal-aware design techniques are urgently demanded at all design abstraction levels. In this book, we present our research efforts to employ real-time scheduling techniques to solve the resource-constrained power/thermal-aware, design-optimization problems. The novelty of this work is that we integrate the cutting-edge research on power and thermal at the circuit and architectural-level into a set of accurate yet simplified system-level models, and are able to conduct system-level analysis and design based on these models. The theoretical study in this work serves as a solid foundation for the guidance of the power/thermal-aware scheduling algorithms development in practical computing systems.

Download or read book Systems Aspects in Organic and Pervasive Computing ARCS 2005 written by Michael Beigl and published by Springer Science & Business Media. This book was released on 2005-03-07 with total page 275 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book constitutes the refereed proceedings of the 18th International Conference on Architecture of Computing Systems, ARCS 2005, held in Innsbruck, Austria in March 2005. The 18 revised full papers presented were carefully reviewed and selected from 52 submissions. The papers are organized in topical sections on adaptation, power consumption, and scheduling; adaptation and agents; adaptation and services; application of adaptable systems; and pervasive computing and communication.

Download or read book Operating System Services for Task Specific Power Management Novel Approaches to Energy Aware Embedded Linux written by Andreas Weifel and published by VDM Publishing. This book was released on 2007 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mobile computing devices like PDAs, cell phones or laptops have become an indispensable part of everyday's life. As these systems are battery-powered and the user expects long operating times, energy-aware operation is crucial. Hardware components for mobile devices offer low-power operating modes that achieve energy savings at the cost of degraded performance or application quality, e.g., by reducing the CPU speed. This dissertation investigates software-controlled energy management and addresses these two, often conflicting goals: increasing the embedded system's runtime by saving energy and providing sufficient application quality. With a cooperative approach between the operating system and individual applications or the user, task-specific trade-offs between these goals can be made. Prototype implementations for embedded Linux are presented and evaluated with energy measurements, proving the feasibility of task-specific power management. This dissertation has a strong practical focus, being a valuable guide for computer scientists and software engineers both in academia and industry who deal with operating system design and low-power software architectures.

Download or read book Towards Energy Efficient Computing with Linux written by Digant Pareshkumar Desai and published by . This book was released on 2013 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: With increasing transistor volume and reducing feature size, it has become a major design constraint to reduce power consumption also. This has given rise to aggressive architectural changes for on-chip power management and rapid development to energy efficient hardware accelerators. Accordingly, the objective of this research work is to facilitate software developers to leverage these hardware techniques and improve energy efficiency of the system. To achieve this, I propose two solutions for Linux kernel: Optimal use of these architectural enhancements to achieve greater energy efficiency requires accurate modeling of processor power consumption. Though there are many models available in literature to model processor power consumption, there is a lack of such models to capture power consumption at the task-level. Task-level energy models are a requirement for an operating system (OS) to perform real-time power management as OS time multiplexes tasks to enable sharing of hardware resources. I propose a detailed design methodology for constructing an architecture agnostic task-level power model and incorporating it into a modern operating system to build an online task-level power profiler. The profiler is implemented inside the latest Linux kernel and validated for Intel Sandy Bridge processor. It has a negligible overhead of less than 1\% hardware resource consumption. The profiler power prediction was demonstrated for various application benchmarks from SPEC to PARSEC with less than 4\% error. I also demonstrate the importance of the proposed profiler for emerging architectural techniques through use case scenarios, which include heterogeneous computing and fine grained per-core DVFS. Along with architectural enhancement in general purpose processors to improve energy efficiency, hardware accelerators like Coarse Grain reconfigurable architecture (CGRA) are gaining popularity. Unlike vector processors, which rely on data parallelism, CGRA can provide greater flexibility and compiler level control making it more suitable for present SoC environment. To provide streamline development environment for CGRA, I propose a flexible framework in Linux to do design space exploration for CGRA. With accurate and flexible hardware models, fine grained integration with accurate architectural simulator, and Linux memory management and DMA support, a user can carry out limitless experiments on CGRA in full system environment.

Download or read book Power aware Scheduling for Real time Embedded Systems written by Linwei Niu and published by . This book was released on 2006 with total page 181 pages. Available in PDF, EPUB and Kindle. Book excerpt: Driven by the remarkable evolution of IC technology and the ever-increasing human appetite for higher computing power, the dramatically increased power/energy consumption for real-time embedded systems has presented a profound challenge to researchers and developers. Battery-operated embedded devices, which have already been ubiquitous, demand low power consumption to extend the battery life and thus the mission cycles. Even for power-rich platforms, rapidly elevated power consumption raised serious concerns regarding the reliability and packaging/cooling cost as a result of the heat dissipation. It is fair to say that energy reduction has become one of the most critical design issues in the design of next generation real-time embedded systems. In our research, we seek to address this problem at the operating system level. Specifically, we believe that real-time scheduling plays a critical role in power/energy reduction not only because most embedded systems have real-time requirements, but also because significant energy savings can be achieved by taking advantage of the knowledge in application characteristics and underlying architectures known at this level. The goal of our research is to study and develop appropriate real-time scheduling techniques that can exploit the advanced power manageable features in state-of-the-art architecture to minimize the power/energy consumption while satisfying other design requirements at the same time. The contributions of the dissertation include: (i) We developed several advanced power-aware scheduling algorithms for hard real-time systems with emphasis on reducing both dynamic and leakage power consumption; (ii) We extended the system model from simple hard real-time systems to soft real-time systems with more complicated Quality of Service constraints; (iii) We also developed efficient scheduling algorithms to minimize the system-wide energy consumption with peripheral devices taken into consideration. Experimental results have demonstrated that our techniques greatly outperform existing ones. The problems discussed in this dissertation are rather general in real-time embedded system designs, and these methodologies and techniques are important both in the theoretical and practical sense.

Download or read book Hard Real Time Computing Systems written by Giorgio C Buttazzo and published by Springer Science & Business Media. This book was released on 2011-09-10 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: This updated edition offers an indispensable exposition on real-time computing, with particular emphasis on predictable scheduling algorithms. It introduces the fundamental concepts of real-time computing, demonstrates the most significant results in the field, and provides the essential methodologies for designing predictable computing systems used to support time-critical control applications. Along with an in-depth guide to the available approaches for the implementation and analysis of real-time applications, this revised edition contains a close examination of recent developments in real-time systems, including limited preemptive scheduling, resource reservation techniques, overload handling algorithms, and adaptive scheduling techniques. This volume serves as a fundamental advanced-level textbook. Each chapter provides basic concepts, which are followed by algorithms, illustrated with concrete examples, figures and tables. Exercises and solutions are provided to enhance self-study, making this an excellent reference for those interested in real-time computing for designing and/or developing predictable control applications.

Download or read book Configuration aware and QoS aware Task Scheduling in Real time Adaptive Embedded Systems written by Hessam Kooti and published by . This book was released on 2012 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: In order to cope with increase in demand for embedded applications under resource and power constraints, there is an increasing trend on incorporating system-level flexibility and runtime adaptation in embedded systems. Although a complete processor-based implementation provides ultimate flexibility, usually computationally intensive processing mandates hardware support in addition to the processors. However, the main drawback of reconfigurable hardware platform is delay and energy overhead during system reconfiguration. Ignoring the time and energy required for reconfiguration may lead to performance degradation and deadline misses. In this thesis we provide different real-time scheduling techniques. First, we propose the first real-time scheduler that is aware of the transition time overhead due to configuration of underlying hardware. We consider a heterogeneous multi-processor system and there are data dependencies among tasks and communication overhead time during task execution. In many applications deadline miss rate is not an accurate metric to model the application quality but the distribution of deadline misses is the main factor. We use a well-known Weakly Hard System QoS model to define the acceptable deadline miss distribution. We provide an online scheduler that considers the time overheads among task switching while the deadline misses caused by time overheads follow a predefined pattern. Next, we focus on energy consumption of the system and provide a scheduler that considers the time and energy overhead during power management. In our work deadline miss rate is minimized as the primary objective and the energy consumption of the system is minimized by means of voltage scaling as the secondary objective. Many adaptive systems need to adapt to varying delay and/or energy constraints such as fluctuation of energy source when system is powered by renewable energies like solar energy. In order to ensure the scheduler can handle the dynamicity in availability of the energy source, we exploit the QoS constraint so the application quality is not violated during job dropout when our power management scheme adjusts the energy consumption according to energy availability. Each of these schedulers is accompanied by an extensive experimental evaluation that represents the effect of using the proposed algorithms.

Download or read book Real Time Systems Design and Analysis written by Phillip A. Laplante and published by Wiley-IEEE Press. This book was released on 1997 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: "IEEE Press is pleased to bring you this Second Edition of Phillip A. Laplante's best-selling and widely-acclaimed practical guide to building real-time systems. This book is essential for improved system designs, faster computation, better insights, and ultimate cost savings. Unlike any other book in the field, REAL-TIME SYSTEMS DESIGN AND ANALYSIS provides a holistic, systems-based approach that is devised to help engineers write problem-solving software. Laplante's no-nonsense guide to real-time system design features practical coverage of: Related technologies and their histories Time-saving tips * Hands-on instructions Pascal code Insights into decreasing ramp-up times and more!"

Download or read book Soft Real Time Systems Predictability vs Efficiency written by Giorgio C Buttazzo and published by Springer Science & Business Media. This book was released on 2006-07-02 with total page 281 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hard real-time systems are very predictable, but not sufficiently flexible to adapt to dynamic situations. They are built under pessimistic assumptions to cope with worst-case scenarios, so they often waste resources. Soft real-time systems are built to reduce resource consumption, tolerate overloads and adapt to system changes. They are also more suited to novel applications of real-time technology, such as multimedia systems, monitoring apparatuses, telecommunication networks, mobile robotics, virtual reality, and interactive computer games. This unique monograph provides concrete methods for building flexible, predictable soft real-time systems, in order to optimize resources and reduce costs. It is an invaluable reference for developers, as well as researchers and students in Computer Science.

Download or read book Conference Proceedings of the 2002 International Conference on Supercomputing written by and published by . This book was released on 2002 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Embedded Linux System Design and Development written by P. Raghavan and published by CRC Press. This book was released on 2005-12-21 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based upon the authors' experience in designing and deploying an embedded Linux system with a variety of applications, Embedded Linux System Design and Development contains a full embedded Linux system development roadmap for systems architects and software programmers. Explaining the issues that arise out of the use of Linux in embedded systems, the book facilitates movement to embedded Linux from traditional real-time operating systems, and describes the system design model containing embedded Linux. This book delivers practical solutions for writing, debugging, and profiling applications and drivers in embedded Linux, and for understanding Linux BSP architecture. It enables you to understand: various drivers such as serial, I2C and USB gadgets; uClinux architecture and its programming model; and the embedded Linux graphics subsystem. The text also promotes learning of methods to reduce system boot time, optimize memory and storage, and find memory leaks and corruption in applications. This volume benefits IT managers in planning to choose an embedded Linux distribution and in creating a roadmap for OS transition. It also describes the application of the Linux licensing model in commercial products.

Download or read book Real Time Systems written by Rajib Mall and published by Pearson Education India. This book was released on 2009-05 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: The presence and use of real-time systems is becoming increasingly common. Examples of such systems range from nuclear reactors, to automotive controllers, and also entertainment software such as games and graphics animation. The growing importance of rea.