Analysis Of Optimal Power Aware Scheduling Techniques In Embedded Systems For The Multiprocessor Platform Running Non Preemptive Jobs
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Analysis Of Optimal Power Aware Scheduling Techniques In Embedded Systems For The Multiprocessor Platform Running Non Preemptive Jobs
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Author : Rahul Ghosh
language : en
Publisher:
Release Date : 2015
Analysis Of Optimal Power Aware Scheduling Techniques In Embedded Systems For The Multiprocessor Platform Running Non Preemptive Jobs written by Rahul Ghosh and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with Computer scheduling categories.
Energy Aware Scheduling On Multiprocessor Platforms
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Author : Dawei Li
language : en
Publisher: Springer Science & Business Media
Release Date : 2012-10-20
Energy Aware Scheduling On Multiprocessor Platforms written by Dawei Li and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012-10-20 with Business & Economics categories.
Multiprocessor platforms play important roles in modern computing systems, and appear in various applications, ranging from energy-limited hand-held devices to large data centers. As the performance requirements increase, energy-consumption in these systems also increases significantly. Dynamic Voltage and Frequency Scaling (DVFS), which allows processors to dynamically adjust the supply voltage and the clock frequency to operate on different power/energy levels, is considered an effective way to achieve the goal of energy-saving. This book surveys existing works that have been on energy-aware task scheduling on DVFS multiprocessor platforms. Energy-aware scheduling problems are intrinsically optimization problems, the formulations of which greatly depend on the platform and task models under consideration. Thus, Energy-aware Scheduling on Multiprocessor Platforms covers current research on this topic and classifies existing works according to two key standards, namely, homogeneity/heterogeneity of multiprocessor platforms and the task types considered. Under this classification, other sub-issues are also included, such as, slack reclamation, fixed/dynamic priority scheduling, partition-based/global scheduling, and application-specific power consumption, etc.
Energy Aware Scheduling For Real Time Embedded Systems
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Author : Muhammad Khurram Bhatti
language : en
Publisher: LAP Lambert Academic Publishing
Release Date : 2012-04
Energy Aware Scheduling For Real Time Embedded Systems written by Muhammad Khurram Bhatti and has been published by LAP Lambert Academic Publishing this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012-04 with categories.
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.
Evaluation Of Power Management Strategies On Actual Multiprocessor Platforms
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Author : Jabran Khan Jadoon
language : en
Publisher:
Release Date : 2013
Evaluation Of Power Management Strategies On Actual Multiprocessor Platforms written by Jabran Khan Jadoon and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with categories.
The purpose of this study is to investigate how power management strategies can be efficiently exploited in actual platforms. Primarily, the challenges in multicore based embedded systems lies in managing the energy expenditure, determining the scheduling behavior and establishing methods to monitor power and energy, so as to meet the demands of the battery life and load requirements. The work presented in this dissertation is a study of low power-aware strategies in the practical world for single and multiprocessor platforms. The approach used for this study is based on representative multiprocessor platforms (real or virtual) to identify the most influential parameters, at hardware as well as application level, unlike many existing works in which these parameters are often underestimated or sometimes even ignored. The work analyzes and compares in detail various experimentations with different power policies based on Dynamic Voltage and Frequency Scaling (DVFS) and Dynamic Power Switching (DPS) techniques, and investigates the conditions at which these policies are effective in terms of energy savings. The results of these investigations reveal many interesting and notable conclusions that can serve as prerequisites for the efficient use of power management strategies. This work also shows the potential of advanced domain specific power strategies compared to real world available strategies that are general purpose based in their majority. Finally, some high level consumption models are derived from the different energy measurement results to let the estimation of power management benefits at early stages of a system development.
Frequency Aware Static Timing Analysis For Power Aware Embedded Architectures
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Author :
language : en
Publisher:
Release Date : 2003
Frequency Aware Static Timing Analysis For Power Aware Embedded Architectures written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2003 with categories.
Power is a valuable resource in embedded systems as the lifetime of many such systems is constrained by their battery capacity. Recent advances in processor design have added support for dynamic frequency/voltage scaling (DVS) for saving power. Recent work on real-time scheduling focuses on saving power in static as well as dynamic scheduling environments by exploiting idle and slack due to early task completion for DVS of subsequent tasks. These scheduling algorithms rely on a priori knowledge of worst-case execution times (WCET) for each task. They assume that DVS has no effect on the worst-case execution cycles (WCEC) of a task and scale the WCET according to the processor frequency. However, for systems with memory hierarchies, the WCEC typically does change under DVS due to frequency modulation. Hence, current assumptions used by DVS schemes result in a highly exaggerated WCET. The research presented contributes novel techniques for tight and flexible static timing analysis particularly well-suited for dynamic scheduling schemes. The technical contributions are as follows: (1) The problem of changing execution cycles due to scaling techniques is assessed. (2) A parametric approach towards bounding the WCET statically with respect to the frequency is proposed. Using a parametric model, the effect of changes in frequency on the WCEC can be captured and, thus, the WCET over any frequency range can be accurately modeled. (3) The design and implementation of the frequency-aware static timing analysis (FAST) tool, based on prior experience with static timing analysis, is discussed. (4) Experiments demonstrate that the FAST tool provides safe upper bounds on the WCET, which are tight. The FAST tool allows the capture of the WCET of six benchmarks using equations that overestimate the WCET by less than 1%. FAST equations can also be used to improve existing DVS scheduling schemes to ensure that the effect of frequency scaling on WCET is considered and that the WCET use.
Proceedings
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Author :
language : en
Publisher:
Release Date : 2005
Proceedings written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005 with Operating systems (Computers) categories.
Real Time Scheduling For Energy Haversting Embedded Systems
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Author : Younès Chandarli
language : en
Publisher:
Release Date : 2014
Real Time Scheduling For Energy Haversting Embedded Systems written by Younès Chandarli and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with categories.
In this thesis, we are interested in the real-time fixed-priority scheduling problem of energy-harvesting systems. An energy-harvesting system is a system that can collect the energy from the environment in order to store it in a storage device and then to use it to supply an electronic device. This technology is used in small embedded systems that are required to run autonomously for a very long lifespan. Wireless sensor networks and medical implants are typical applications of this technology. Moreover, most of these devices have to execute many recurrent tasks within a limited time. Thus, these devices are subject to real-time constraints where the correctness of the system depends not only on the correctness of the results but also on the time in which they are delivered. This thesis focuses on the preemptive fixed-task-priority real-time scheduling for such systems in monoprocessor platforms. The problematic here is to find efficient scheduling algorithms and schedulability conditions that check the schedulability of a given task set in a given energy configuration. The first result of this thesis is the proposition of the PFPasap scheduling algorithm. It is an adaptation of the classical fixed-task-priority scheduling to the energy-harvesting context. It consists of executing tasks as soon as possible whenever the energy is sufficient to execute at least one time unit and replenishes otherwise. The replenishment periods are as long as needed to execute one time unit. We prove that PFPasap is optimal but only in the case of non-concrete systems where the first release time of tasks and the initial energy storage unit level are known only at run-time and where all the tasks consume more energy than the replenishment during execution times. A sufficient and necessary schedulability condition for such systems is also proposed. Unfortunately, when we relax the assumption of tasks energy consumption profile, by considering both tasks that consume more energy than the replenishment and the ones that consume less than the replenishment, PFPasap is no longer optimal and the worst-case scenario is no longer the synchronous release of all the tasks, which makes the precedent schedulability test only necessary. To cope with this limitation, we propose to upper bound tasks worst-case response time in order to build sufficient schedulability conditions instead of exact ones. Regarding algorithms optimality, we explore different ideas in order to build an optimal algorithm for the general model of fixed-task-priority tasks by considering all types of task sets and energy consumption profiles. We show through some counter examples the difficulty of finding such an algorithm and we show that most of intuitive scheduling algorithms are not optimal. After that, we discuss the possibility of finding such an algorithm. In order to better understand the scheduling problematic of fixed-priority scheduling for energy-harvesting systems, we also try to explore the solutions of similar scheduling problematics, especially the ones that delay executions in order to guarantee some requirements. The thermal-aware scheduling is one of these problematics. It consists of executing tasks such that a maximum temperature is never exceeded. This may lead to introduce additional idle times to cool down the system in order to prevent reaching the maximum temperature. As a first step, we propose in this thesis to adapt the solutions proposed for energy-harvesting systems to the thermal-aware model. Thus, we adapt the PFPasap algorithm to respect the thermal constraints and we propose a sufficient schedulability analysis based on worst-case response time upper bounds. Finally, we present YARTISS: the simulation tool used to evaluate the theoretical results presented in this dissertation.
Configuration Aware And Qos Aware Task Scheduling In Real Time Adaptive Embedded Systems
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Author : Hessam Kooti
language : en
Publisher:
Release Date : 2012
Configuration Aware And Qos Aware Task Scheduling In Real Time Adaptive Embedded Systems written by Hessam Kooti and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with categories.
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.
Embedded System Design
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Author : Peter Marwedel
language : en
Publisher: Springer Science & Business Media
Release Date : 2010-11-16
Embedded System Design written by Peter Marwedel and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010-11-16 with Technology & Engineering categories.
Until the late 1980s, information processing was associated with large mainframe computers and huge tape drives. During the 1990s, this trend shifted toward information processing with personal computers, or PCs. The trend toward miniaturization continues and in the future the majority of information processing systems will be small mobile computers, many of which will be embedded into larger products and interfaced to the physical environment. Hence, these kinds of systems are called embedded systems. Embedded systems together with their physical environment are called cyber-physical systems. Examples include systems such as transportation and fabrication equipment. It is expected that the total market volume of embedded systems will be significantly larger than that of traditional information processing systems such as PCs and mainframes. Embedded systems share a number of common characteristics. For example, they must be dependable, efficient, meet real-time constraints and require customized user interfaces (instead of generic keyboard and mouse interfaces). Therefore, it makes sense to consider common principles of embedded system design. Embedded System Design starts with an introduction into the area 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, like real-time operating systems. The book also discusses evaluation and validation techniques for embedded systems. Furthermore, the book presents an overview of techniques for mapping applications to execution platforms. Due to the importance of resource efficiency, the book also contains a selected set of optimization techniques for embedded systems, including special compilation techniques. The book closes with a brief survey on testing. Embedded System Design can be used as a text book for courses on embedded systems and as a source which provides pointers to relevant material in the area for PhD students and teachers. It assumes a basic knowledge of information processing hardware and software. Courseware related to this book is available at http://ls12-www.cs.tu-dortmund.de/~marwedel.
Power Aware Computer Systems
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Author : Babak Falsafi
language : en
Publisher: Springer Science & Business Media
Release Date : 2005-12-12
Power Aware Computer Systems written by Babak Falsafi and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005-12-12 with Computers categories.
This book contributes the thoroughly refereed post-proceedings of the 4th International Workshop on Power-Aware Computer Systems, PACS 2004, held in Portland, OR, USA in December 2004. The 12 revised full papers presented were carefully reviewed, selected, and revised for inclusion in the book. The papers span a wide spectrum of topics in power-aware systems; they are organized in topical sections on microarchitecture- and circuit-level techniques, power-aware memory and interconnect systems, and frequency- and voltage-scaling techniques.