Software-controlled operand-gating

Operand gating is a technique for improving processor energy efficiency by gating off sections of the data path that are unneeded by short-precision (narrow) operands. A method for implementing software-controlled power gating is proposed and evaluated. The instruction set architecture (ISA) is enhanced to include opcodes that specify operand widths (if not already included in the ISA). A compiler or a binary translator uses statically available information to determine initial value ranges. The technique is enhanced through a profile-based analysis that results in the specialization of certain code regions for a given value range. After the analysis, instruction opcodes are assigned using the minimum required width. To evaluate this technique the Alpha instruction set is enhanced to include opcodes for 8, 16, and 32 bit operands. Applying the proposed software technique to the Speclnt95 benchmarks results in energy-delay savings of 14%. When combined with previously proposed hardware-based techniques, the energy-delay benefit is 28%.Peer ReviewedPostprint (published version

Empowering a helper cluster through data-width aware instruction selection policies

Narrow values that can be represented by less number of bits than the full machine width occur very frequently in programs. On the other hand, clustering mechanisms enable cost- and performance-effective scaling of processor back-end features. Those attributes can be combined synergistically to design special clusters operating on narrow values (a.k.a. helper cluster), potentially providing performance benefits. We complement a 32-bit monolithic processor with a low-complexity 8-bit helper cluster. Then, in our main focus, we propose various ideas to select suitable instructions to execute in the data-width based clusters. We add data-width information as another instruction steering decision metric and introduce new data-width based selection algorithms which also consider dependency, inter-cluster communication and load imbalance. Utilizing those techniques, the performance of a wide range of workloads are substantially increased; helper cluster achieves an average speedup of 11% for a wide range of 412 apps. When focusing on integer applications, the speedup can be as high as 22% on averagePeer ReviewedPostprint (published version

The impact of design techniques in the reduction of power consumption of SoCs Multimedia

Orientador: Guido Costa Souza de AraújoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: A indústria de semicondutores sempre enfrentou fortes demandas em resolver problema de dissipação de calor e reduzir o consumo de energia em dispositivos. Esta tendência tem sido intensificada nos últimos anos com o movimento de sustentabilidade ambiental. A concepção correta de um sistema eletrônico de baixo consumo de energia é um problema de vários níveis de complexidade e exige estratégias sistemáticas na sua construção. Fora disso, a adoção de qualquer técnica de redução de energia sempre está vinculada com objetivos especiais e provoca alguns impactos no projeto. Apesar dos projetistas conheçam bem os impactos de forma qualitativa, as detalhes quantitativas ainda são incógnitas ou apenas mantidas dentro do 'know-how' das empresas. Neste trabalho, de acordo com resultados experimentais baseado num plataforma de SoC1 industrial, tentamos quantificar os impactos derivados do uso de técnicas de redução de consumo de energia. Nos concentramos em relacionar o fator de redução de energia de cada técnica aos impactos em termo de área, desempenho, esforço de implementação e verificação. Na ausência desse tipo de dados, que relacionam o esforço de engenharia com as metas de consumo de energia, incertezas e atrasos serão frequentes no cronograma de projeto. Esperamos que este tipo de orientações possam ajudar/guiar os arquitetos de projeto em selecionar as técnicas adequadas para reduzir o consumo de energia dentro do alcance de orçamento e cronograma de projetoAbstract: The semiconductor industry has always faced strong demands to solve the problem of heat dissipation and reduce the power consumption in electronic devices. This trend has been increased in recent years with the action of environmental sustainability. The correct conception of an electronic system for low power consumption is an issue with multiple levels of complexities and requires systematic approaches in its construction. However, the adoption of any technique for reducing the power consumption is always linked with some specific goals and causes some impacts on the project. Although the designers know well that these impacts can affect the design in a quality aspect, the quantitative details are still unkown or just be kept inside the company's know-how. In this work, according to the experimental results based on an industrial SoC2 platform, we try to quantify the impacts of the use of low power techniques. We will relate the power reduction factor of each technique to the impact in terms of area, performance, implementation and verification effort. In the absence of such data, which relates the engineering effort to the goals of power consumption, uncertainties and delays are frequent. We hope that such guidelines can help/guide the project architects in selecting the appropriate techniques to reduce the power consumption within the limit of budget and project scheduleMestradoCiência da ComputaçãoMestre em Ciência da Computaçã

ASIC implemented MicroBlaze-based Coprocessor for Data Stream Management Systems

Indiana University-Purdue University Indianapolis (IUPUI)The drastic increase in Internet usage demands the need for processing data in real time with higher efficiency than ever before. Symbiote Coprocessor Unit (SCU), developed by Dr. Pranav Vaidya, is a hardware accelerator which has potential of providing data processing speedup of up to 150x compared with traditional data stream processors. However, SCU implementation is very complex, fixed, and uses an outdated host interface, which limits future improvement. Mr. Tareq S. Alqaisi, an MSECE graduate from IUPUI worked on curbing these limitations. In his architecture, he used a Xilinx MicroBlaze microcontroller to reduce the complexity of SCU along with few other modifications. The objective of this study is to make SCU suitable for mass production while reducing its power consumption and delay. To accomplish this, the execution unit of SCU has been implemented in application specific integrated circuit and modules such as ACG/OCG, sequential comparator, and D-word multiplier/divider are integrated into the design. Furthermore, techniques such as operand isolation, buffer insertion, cell swapping, and cell resizing are also integrated into the system. As a result, the new design attains 67.9435 µW of dynamic power as compared to 74.0012 µW before power optimization along with a small increase in static power, 39.47 ns of clock period as opposed to 52.26 ns before time optimization

MULTIPAC, a multiple pool processor and computer for a spacecraft central data system, phase 2 Final report

MULTIPAC, multiple pool processor and computer for deep space probe central data syste

A hardware mechanism to reduce the energy consumption of the register file of in-order architectures

This paper introduces an efficient hardware approach to reduce the register file energy consumption by turning unused registers into a low power state. Bypassing the register fields of the fetch instruction to the decode stage allows the identification of registers required by the current instruction (instruction predecode) and allows the control logic to turn them back on. They are put into the low-power state after the instruction use. This technique achieves an 85% energy reduction with no performance penalty

Chapter One – An Overview of Architecture-Level Power- and Energy-Efficient Design Techniques

Power dissipation and energy consumption became the primary design constraint for almost all computer systems in the last 15 years. Both computer architects and circuit designers intent to reduce power and energy (without a performance degradation) at all design levels, as it is currently the main obstacle to continue with further scaling according to Moore's law. The aim of this survey is to provide a comprehensive overview of power- and energy-efficient “state-of-the-art” techniques. We classify techniques by component where they apply to, which is the most natural way from a designer point of view. We further divide the techniques by the component of power/energy they optimize (static or dynamic), covering in that way complete low-power design flow at the architectural level. At the end, we conclude that only a holistic approach that assumes optimizations at all design levels can lead to significant savings.Peer ReviewedPostprint (published version

Computer recommendations for an automatic approach and landing system for V/STOL aircraft. Volume 1 - Computer recommendations

Evaluation of digital computer for V/STOL aircraft automatic approach and landing syste

Energy Aware Design and Analysis for Synchronous and Asynchronous Circuits

Power dissipation has become a major concern for IC designers. Various low power design techniques have been developed for synchronous circuits. Asynchronous circuits, however. have gained more interests recently due to their benefits in lower noise, easy timing control, etc. But few publications on energy reduction techniques for asynchronous logic are available. Power awareness indicates the ability of the system power to scale with changing conditions and quality requirements. Scalability is an important figure-of-merit since it allows the end user to implement operational policy. just like the user of mobile multimedia equipment needs to select between better quality and longer battery operation time. This dissertation discusses power/energy optimization and performs analysis on both synchronous and asynchronous logic. The major contributions of this dissertation include: 1 ) A 2-Dimensional Pipeline Gating technique for synchronous pipelined circuits to improve their power awareness has been proposed. This technique gates the corresponding clock lines connected to registers in both vertical direction (the data flow direction) and horizontal direction (registers within each pipeline stage) based on current input precision. 2) Two energy reduction techniques, Signal Bypassing & Insertion and Zero Insertion. have been developed for NCL circuits. Both techniques use Nulls to replace redundant Data 0\u27s based on current input precision in order to reduce the switching activity while Signal Bypassing & Insertion is for non-pipelined NCI, circuits and Zero Insertion is for pipelined counterparts. A dynamic active-bit detection scheme is also developed as an expansion. 3) Two energy estimation techniques, Equivalent Inverter Modeling based on Input Mapping in transistor-level and Switching Activity Modeling in gate-level, have been proposed. The former one is for CMOS gates with feedbacks and the latter one is for NCL circuits