Analysis of Body Bias Control Using Overhead Conditions for Real Time Systems: a Practical Approach∗
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Pipelining and Vector Processing
Chapter 8 Pipelining and Vector Processing 8–1 If the pipeline stages are heterogeneous, the slowest stage determines the flow rate of the entire pipeline. This leads to other stages idling. 8–2 Pipeline stalls can be caused by three types of hazards: resource, data, and control hazards. Re- source hazards result when two or more instructions in the pipeline want to use the same resource. Such resource conflicts can result in serialized execution, reducing the scope for overlapped exe- cution. Data hazards are caused by data dependencies among the instructions in the pipeline. As a simple example, suppose that the result produced by instruction I1 is needed as an input to instruction I2. We have to stall the pipeline until I1 has written the result so that I2 reads the correct input. If the pipeline is not designed properly, data hazards can produce wrong results by using incorrect operands. Therefore, we have to worry about the correctness first. Control hazards are caused by control dependencies. As an example, consider the flow control altered by a branch instruction. If the branch is not taken, we can proceed with the instructions in the pipeline. But, if the branch is taken, we have to throw away all the instructions that are in the pipeline and fill the pipeline with instructions at the branch target. 8–3 Prefetching is a technique used to handle resource conflicts. Pipelining typically uses just-in- time mechanism so that only a simple buffer is needed between the stages. We can minimize the performance impact if we relax this constraint by allowing a queue instead of a single buffer. -
Diploma Thesis
Faculty of Computer Science Chair for Real Time Systems Diploma Thesis Timing Analysis in Software Development Author: Martin Däumler Supervisors: Jun.-Prof. Dr.-Ing. Robert Baumgartl Dr.-Ing. Andreas Zagler Date of Submission: March 31, 2008 Martin Däumler Timing Analysis in Software Development Diploma Thesis, Chemnitz University of Technology, 2008 Abstract Rapid development processes and higher customer requirements lead to increasing inte- gration of software solutions in the automotive industry’s products. Today, several elec- tronic control units communicate by bus systems like CAN and provide computation of complex algorithms. This increasingly requires a controlled timing behavior. The following diploma thesis investigates how the timing analysis tool SymTA/S can be used in the software development process of the ZF Friedrichshafen AG. Within the scope of several scenarios, the benefits of using it, the difficulties in using it and the questions that can not be answered by the timing analysis tool are examined. Contents List of Figures iv List of Tables vi 1 Introduction 1 2 Execution Time Analysis 3 2.1 Preface . 3 2.2 Dynamic WCET Analysis . 4 2.2.1 Methods . 4 2.2.2 Problems . 4 2.3 Static WCET Analysis . 6 2.3.1 Methods . 6 2.3.2 Problems . 7 2.4 Hybrid WCET Analysis . 9 2.5 Survey of Tools: State of the Art . 9 2.5.1 aiT . 9 2.5.2 Bound-T . 11 2.5.3 Chronos . 12 2.5.4 MTime . 13 2.5.5 Tessy . 14 2.5.6 Further Tools . 15 2.6 Examination of Methods . 16 2.6.1 Software Description . -
Instruction-Level Distributed Processing
COVER FEATURE Instruction-Level Distributed Processing Shifts in hardware and software technology will soon force designers to look at microarchitectures that process instruction streams in a highly distributed fashion. James E. or nearly 20 years, microarchitecture research In short, the current focus on instruction-level Smith has emphasized instruction-level parallelism, parallelism will shift to instruction-level distributed University of which improves performance by increasing the processing (ILDP), emphasizing interinstruction com- Wisconsin- number of instructions per cycle. In striving munication with dynamic optimization and a tight Madison F for such parallelism, researchers have taken interaction between hardware and low-level software. microarchitectures from pipelining to superscalar pro- cessing, pushing toward increasingly parallel proces- TECHNOLOGY SHIFTS sors. They have concentrated on wider instruction fetch, During the next two or three technology generations, higher instruction issue rates, larger instruction win- processor architects will face several major challenges. dows, and increasing use of prediction and speculation. On-chip wire delays are becoming critical, and power In short, researchers have exploited advances in chip considerations will temper the availability of billions of technology to develop complex, hardware-intensive transistors. Many important applications will be object- processors. oriented and multithreaded and will consist of numer- Benefiting from ever-increasing transistor budgets ous separately -
How Data Hazards Can Be Removed Effectively
International Journal of Scientific & Engineering Research, Volume 7, Issue 9, September-2016 116 ISSN 2229-5518 How Data Hazards can be removed effectively Muhammad Zeeshan, Saadia Anayat, Rabia and Nabila Rehman Abstract—For fast Processing of instructions in computer architecture, the most frequently used technique is Pipelining technique, the Pipelining is consider an important implementation technique used in computer hardware for multi-processing of instructions. Although multiple instructions can be executed at the same time with the help of pipelining, but sometimes multi-processing create a critical situation that altered the normal CPU executions in expected way, sometime it may cause processing delay and produce incorrect computational results than expected. This situation is known as hazard. Pipelining processing increase the processing speed of the CPU but these Hazards that accrue due to multi-processing may sometime decrease the CPU processing. Hazards can be needed to handle properly at the beginning otherwise it causes serious damage to pipelining processing or overall performance of computation can be effected. Data hazard is one from three types of pipeline hazards. It may result in Race condition if we ignore a data hazard, so it is essential to resolve data hazards properly. In this paper, we tries to present some ideas to deal with data hazards are presented i.e. introduce idea how data hazards are harmful for processing and what is the cause of data hazards, why data hazard accord, how we remove data hazards effectively. While pipelining is very useful but there are several complications and serious issue that may occurred related to pipelining i.e. -
45-Year CPU Evolution: One Law and Two Equations
45-year CPU evolution: one law and two equations Daniel Etiemble LRI-CNRS University Paris Sud Orsay, France [email protected] Abstract— Moore’s law and two equations allow to explain the a) IC is the instruction count. main trends of CPU evolution since MOS technologies have been b) CPI is the clock cycles per instruction and IPC = 1/CPI is the used to implement microprocessors. Instruction count per clock cycle. c) Tc is the clock cycle time and F=1/Tc is the clock frequency. Keywords—Moore’s law, execution time, CM0S power dissipation. The Power dissipation of CMOS circuits is the second I. INTRODUCTION equation (2). CMOS power dissipation is decomposed into static and dynamic powers. For dynamic power, Vdd is the power A new era started when MOS technologies were used to supply, F is the clock frequency, ΣCi is the sum of gate and build microprocessors. After pMOS (Intel 4004 in 1971) and interconnection capacitances and α is the average percentage of nMOS (Intel 8080 in 1974), CMOS became quickly the leading switching capacitances: α is the activity factor of the overall technology, used by Intel since 1985 with 80386 CPU. circuit MOS technologies obey an empirical law, stated in 1965 and 2 Pd = Pdstatic + α x ΣCi x Vdd x F (2) known as Moore’s law: the number of transistors integrated on a chip doubles every N months. Fig. 1 presents the evolution for II. CONSEQUENCES OF MOORE LAW DRAM memories, processors (MPU) and three types of read- only memories [1]. The growth rate decreases with years, from A. -
Pipelining: Basic Concepts and Approaches
International Journal of Scientific & Engineering Research, Volume 7, Issue 4, April-2016 1197 ISSN 2229-5518 Pipelining: Basic Concepts and Approaches RICHA BAIJAL1 1Student,M.Tech,Computer Science And Engineering Career Point University,Alaniya,Jhalawar Road,Kota-325003 (Rajasthan) Abstract-This paper is concerned with the pipelining principles while designing a processor.The basics of instruction pipeline are discussed and an approach to minimize a pipeline stall is explained with the help of example.The main idea is to understand the working of a pipeline in a processor.Various hazards that cause pipeline degradation are explained and solutions to minimize them are discussed. Index Terms— Data dependency, Hazards in pipeline, Instruction dependency, parallelism, Pipelining, Processor, Stall. —————————— —————————— 1 INTRODUCTION does the paint. Still,2 rooms are idle. These rooms that I want to paint constitute my hardware.The painter and his skills are the objects and the way i am using them refers to the stag- O understand what pipelining is,let us consider the as- T es.Now,it is quite possible i limit my resources,i.e. I just have sembly line manufacturing of a car.If you have ever gone to a two buckets of paint at a time;therefore,i have to wait until machine work shop ; you might have seen the different as- these two stages give me an output.Although,these are inde- pendent tasks,but what i am limiting is the resources. semblies developed for developing its chasis,adding a part to I hope having this comcept in mind,now the reader -
Powerpc 601 RISC Microprocessor Users Manual
MPR601UM-01 MPC601UM/AD PowerPC™ 601 RISC Microprocessor User's Manual CONTENTS Paragraph Page Title Number Number About This Book Audience .............................................................................................................. xlii Organization......................................................................................................... xlii Additional Reading ............................................................................................. xliv Conventions ........................................................................................................ xliv Acronyms and Abbreviations ............................................................................. xliv Terminology Conventions ................................................................................. xlvii Chapter 1 Overview 1.1 PowerPC 601 Microprocessor Overview............................................................. 1-1 1.1.1 601 Features..................................................................................................... 1-2 1.1.2 Block Diagram................................................................................................. 1-3 1.1.3 Instruction Unit................................................................................................ 1-5 1.1.3.1 Instruction Queue......................................................................................... 1-5 1.1.4 Independent Execution Units.......................................................................... -
Cuda C Best Practices Guide
CUDA C BEST PRACTICES GUIDE DG-05603-001_v9.0 | June 2018 Design Guide TABLE OF CONTENTS Preface............................................................................................................ vii What Is This Document?..................................................................................... vii Who Should Read This Guide?...............................................................................vii Assess, Parallelize, Optimize, Deploy.....................................................................viii Assess........................................................................................................ viii Parallelize.................................................................................................... ix Optimize...................................................................................................... ix Deploy.........................................................................................................ix Recommendations and Best Practices.......................................................................x Chapter 1. Assessing Your Application.......................................................................1 Chapter 2. Heterogeneous Computing.......................................................................2 2.1. Differences between Host and Device................................................................ 2 2.2. What Runs on a CUDA-Enabled Device?...............................................................3 Chapter 3. Application Profiling............................................................................. -
Clock Gating for Power Optimization in ASIC Design Cycle: Theory & Practice
Clock Gating for Power Optimization in ASIC Design Cycle: Theory & Practice Jairam S, Madhusudan Rao, Jithendra Srinivas, Parimala Vishwanath, Udayakumar H, Jagdish Rao SoC Center of Excellence, Texas Instruments, India (sjairam, bgm-rao, jithendra, pari, uday, j-rao) @ti.com 1 AGENDA • Introduction • Combinational Clock Gating – State of the art – Open problems • Sequential Clock Gating – State of the art – Open problems • Clock Power Analysis and Estimation • Clock Gating In Design Flows JS/BGM – ISLPED08 2 AGENDA • Introduction • Combinational Clock Gating – State of the art – Open problems • Sequential Clock Gating – State of the art – Open problems • Clock Power Analysis and Estimation • Clock Gating In Design Flows JS/BGM – ISLPED08 3 Clock Gating Overview JS/BGM – ISLPED08 4 Clock Gating Overview • System level gating: Turn off entire block disabling all functionality. • Conditions for disabling identified by the designer JS/BGM – ISLPED08 4 Clock Gating Overview • System level gating: Turn off entire block disabling all functionality. • Conditions for disabling identified by the designer • Suspend clocks selectively • No change to functionality • Specific to circuit structure • Possible to automate gating at RTL or gate-level JS/BGM – ISLPED08 4 Clock Network Power JS/BGM – ISLPED08 5 Clock Network Power • Clock network power consists of JS/BGM – ISLPED08 5 Clock Network Power • Clock network power consists of – Clock Tree Buffer Power JS/BGM – ISLPED08 5 Clock Network Power • Clock network power consists of – Clock Tree Buffer -
Saber Eletrônica, Designers Pois Precisamos Comprovar Ao Meio Anunciante Estes Números E, Assim, Carlos C
editorial Editora Saber Ltda. Digital Freemium Edition Diretor Hélio Fittipaldi Nesta edição comemoramos o fantástico número de 258.395 downloads da edição 460 digital em PDF que tivemos nos primeiros 50 dias de circu- www.sabereletronica.com.br lação. Assim, esperamos atingir meio milhão em twitter.com/editora_saber seis meses. Na fase de teste, no ano passado, com Editor e Diretor Responsável a Edição Digital Gratuita que chamamos de “Digital Hélio Fittipaldi Conselho Editorial Freemium (Free + Premium) Edition”, já atingimos João Antonio Zuffo este marco e até ultrapassamos. Redação Fica aqui nosso agradecimento a todos os que Hélio Fittipaldi Augusto Heiss seguiram nosso apelo, para somente fazerem Revisão Técnica Eutíquio Lopez download das nossas edições através do link do Portal Saber Eletrônica, Designers pois precisamos comprovar ao meio anunciante estes números e, assim, Carlos C. Tartaglioni, Diego M. Gomes obtermos patrocínio para manter a edição digital gratuita. Publicidade Aproveitamos também para avisar aos nossos leitores de Portugal, Caroline Ferreira, cerca de 6.000 pessoas, que infelizmente os custos para enviarmos as Nikole Barros revistas impressas em papel têm sido altos e, por solicitação do nosso Colaboradores Alexandre Capelli, distribuidor, não enviaremos mais os exemplares impressos em papel Bruno Venâncio, para distribuição no mercado português e ex-colônias na África. César Cassiolato, Dante J. S. Conti, Em junho teremos a edição especial deste semestre e o assunto prin- Edriano C. de Araújo, cipal é a eletrônica embutida (embedded electronic), ou como dizem os Eutíquio Lopez, Tsunehiro Yamabe espanhóis e portugueses: electrónica embebida. Como marco teremos também no Centro de Exposições Transamérica em São Paulo, a 2ª edição da ESC Brazil 2012 e a 1ª MD&M, o maior evento de tecnologia para o mercado de design eletrônico que, neste ano, estará sendo promovido PARA ANUNCIAR: (11) 2095-5339 pela UBM junto com o primeiro evento para o setor médico/odontoló- [email protected] gico (a MD&M Brazil). -
Multi-Cycle Datapathoperation
Book's Definition of Performance • For some program running on machine X, PerformanceX = 1 / Execution timeX • "X is n times faster than Y" PerformanceX / PerformanceY = n • Problem: – machine A runs a program in 20 seconds – machine B runs the same program in 25 seconds 1 Example • Our favorite program runs in 10 seconds on computer A, which hasa 400 Mhz. clock. We are trying to help a computer designer build a new machine B, that will run this program in 6 seconds. The designer can use new (or perhaps more expensive) technology to substantially increase the clock rate, but has informed us that this increase will affect the rest of the CPU design, causing machine B to require 1.2 times as many clockcycles as machine A for the same program. What clock rate should we tellthe designer to target?" • Don't Panic, can easily work this out from basic principles 2 Now that we understand cycles • A given program will require – some number of instructions (machine instructions) – some number of cycles – some number of seconds • We have a vocabulary that relates these quantities: – cycle time (seconds per cycle) – clock rate (cycles per second) – CPI (cycles per instruction) a floating point intensive application might have a higher CPI – MIPS (millions of instructions per second) this would be higher for a program using simple instructions 3 Performance • Performance is determined by execution time • Do any of the other variables equal performance? – # of cycles to execute program? – # of instructions in program? – # of cycles per second? – average # of cycles per instruction? – average # of instructions per second? • Common pitfall: thinking one of the variables is indicative of performance when it really isn’t. -
CS2504: Computer Organization
CS2504, Spring'2007 ©Dimitris Nikolopoulos CS2504: Computer Organization Lecture 4: Evaluating Performance Instructor: Dimitris Nikolopoulos Guest Lecturer: Matthew Curtis-Maury CS2504, Spring'2007 ©Dimitris Nikolopoulos Understanding Performance Why do we study performance? Evaluate during design Evaluate before purchasing Key to understanding underlying organizational motivation How can we (meaningfully) compare two machines? Performance, Cost, Value, etc Main issue: Need to understand what factors in the architecture contribute to overall system performance and the relative importance of these factors Effects of ISA on performance 2 How will hardware change affect performance CS2504, Spring'2007 ©Dimitris Nikolopoulos Airplane Performance Analogy Airplane Passengers Range Speed Boeing 777 375 4630 610 Boeing 747 470 4150 610 Concorde 132 4000 1250 Douglas DC-8-50 146 8720 544 Fighter Jet 4 2000 1500 What metric do we use? Concorde is 2.05 times faster than the 747 747 has 1.74 times higher throughput What about cost? And the winner is: It Depends! 3 CS2504, Spring'2007 ©Dimitris Nikolopoulos Throughput vs. Response Time Response Time: Execution time (e.g. seconds or clock ticks) How long does the program take to execute? How long do I have to wait for a result? Throughput: Rate of completion (e.g. results per second/tick) What is the average execution time of the program? Measure of total work done Upgrading to a newer processor will improve: response time Adding processors to the system will improve: throughput 4 CS2504, Spring'2007 ©Dimitris Nikolopoulos Example: Throughput vs. Response Time Suppose we know that an application that uses both a desktop client and a remote server is limited by network performance.