Energy-aware embedded media processing: customizable memory subsystems and energy management policies

textThe design of energy-efficient data memory architectures for embedded system platforms has received considerable attention in recent years. In this dissertation we propose a special-purpose data memory subsystem, called Xtream-Fit, targeted to streaming media applications executing on both generic uniprocessor embedded platforms and powerful SMT-based multi-threading platforms. We empirically demonstrate that Xtream-Fit achieves high energydelay efficiency across a wide range of media devices, from systems running a single media application to systems concurrently executing multiple media applications under synchronization constraints. Xtream-Fit’s energy efficiency is predicated on a novel task-based execution model that exposes/enhances opportunities for efficient prefetching, and aggressive dynamic energy conservation techniques targeting on-chip and off-chip memory components. A key novelty of Xtream-Fit is that it exposes a single customization parameter, thus enabling a very simple and yet effective design space exploration methodology to find the best memory configuration for the target application(s). Extensive experimental results show that Xtream-Fit reduces energy-delay product substantially – by 32% to 69% – as compared to ‘standard’ general-purpose memory subsystems enhanced with state of the art cache decay and SDRAM power mode control policies.Electrical and Computer Engineerin

Performance Tuning of Streaming Applications via Search-space Decomposition

High-performance streaming applications are typically pipelined and deployed on architecturally diverse (hybrid)systems. Developers of such applications are interested in customizing components used, so as to benefit application performance. We present an efficient and automatic technique for design-space exploration of applications in this problem domain. We solve performance tuning as an optimization problem by formulating cost functions using results from queueing theory. This results in a mixed-integer nonlinear optimization problem which is NP-hard. We reduce the search complexity by decomposing the search space. We have developed a domain-specific decomposition technique using topological information of the application embodied in the queueing network models. Our analysis includes when our decomposition preserves optimality. Our preliminary empirical results confirm two-fold benefits--solving a problem that is currently not solvable using state-of-the-art solvers and in some problem instances, improving initial solution value from the solver by over two orders of magnitude

Processor Enhancements for Media Streaming Applications

The development of more processing demanding applications on the Internet (video broadcasting) on one hand and the popularity of recent devices at the user level (digital cameras, wireless videophones, ...) on the other hand introduce challenges at several levels. Today, such devices present processing capabilities and bandwidth settings that are inefficient to manage scalable QoS requirements in a typical media delivery framework. In this paper, we present an impact study of such a scalable data representation optimized for QoS (Matching Pursuit 3D algorithms) on processor architectures to achieve the best performance and power efficiency. A review of state of the art techniques for processor architecture enhancement let us expect promising opportunities from the latest developments in the reconfigurable computing research field. We present here the first design steps of an efficient reconfigurable coprocessor especially designed to cope with future video delivery and multimedia processing requirements. Architecture perspectives are proposed with respect to low development cost constraints, backward compatibilty and easy coprocessor usage using an original strategy based on a hardware/software codesign methodolog

A Survey of Techniques For Improving Energy Efficiency in Embedded Computing Systems

Recent technological advances have greatly improved the performance and features of embedded systems. With the number of just mobile devices now reaching nearly equal to the population of earth, embedded systems have truly become ubiquitous. These trends, however, have also made the task of managing their power consumption extremely challenging. In recent years, several techniques have been proposed to address this issue. In this paper, we survey the techniques for managing power consumption of embedded systems. We discuss the need of power management and provide a classification of the techniques on several important parameters to highlight their similarities and differences. This paper is intended to help the researchers and application-developers in gaining insights into the working of power management techniques and designing even more efficient high-performance embedded systems of tomorrow