CS 152 Computer Architecture and Engineering Lecture 1 Introduction Krste Asanovic Electrical Engineering and Computer Sciences University of California at Berkeley http www eecs berkeley edu krste http inst eecs berkeley edu cs152 Computing Devices Then EDSAC University of Cambridge UK 1949 1 22 2008 CS152 Spring 08 2 Computing Devices Now Sensor Nets Cameras Media Players Set top boxes Laptops Servers Routers Smart phones Automobiles 1 22 2008 Games Robots Supercomputers CS152 Spring 08 3 What is Computer Architecture Application Gap too large to bridge in one step but there are exceptions e g magnetic compass Physics In its broadest definition computer architecture is the design of the abstraction layers that allow us to implement information processing applications efficiently using available manufacturing technologies 1 22 2008 CS152 Spring 08 4 Abstraction Layers in Modern Systems Application Algorithm Programming Language Original domain of the computer architect 50s 80s Operating System Virtual Machines Instruction Set Architecture ISA Microarchitecture Gates Register Transfer Level RTL Circuits Domain of recent computer architecture 90s Devices Physics 1 22 2008 5 CS152 Spring 08 Uniprocessor Performance 10000 Performance vs VAX 11 780 From Hennessy and Patterson Computer Architecture A Quantitative Approach 4th edition October 2006 year 1000 52 year 100 10 25 year d e en p p ha t a Wh 1 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 VAX 25 year 1978 to 1986 RISC x86 52 year 1986 to 2002 RISC x86 year 2002 to present 1 22 2008 CS152 Spring 08 6 The End of the Uniprocessor Era Single biggest change in the history of computing systems 1 22 2008 CS152 Spring 08 7 Conventional Wisdom in Computer Architecture Old Conventional Wisdom Power is free Transistors expensive New Conventional Wisdom Power wall Power expensive Transistors free Can put more on chip than can afford to turn on Old CW Sufficient increasing Instruction Level Parallelism via compilers innovation pipelining superscalar out of order speculation VLIW New CW ILP wall law of diminishing returns on more HW for ILP Old CW Multiplies are slow Memory access is fast New CW Memory wall Memory slow multiplies fast 200 clock cycles to DRAM memory 4 clocks for multiply Old CW Uniprocessor performance 2X 1 5 yrs New CW Power Wall ILP Wall Memory Wall Brick Wall Uniprocessor performance now 2X 5 yrs Sea change in chip design multiple cores 2X processors per chip 2 years More simpler processors are more power efficient 1 22 2008 CS152 Spring 08 8 Sea Change in Chip Design Intel 4004 1971 4 bit processor 2312 transistors 0 4 MHz 10 micron PMOS 11 mm2 chip RISC II 1983 32 bit 5 stage pipeline 40 760 transistors 3 MHz 3 micron NMOS 60 mm2 chip 125 mm2 chip 0 065 micron CMOS 2312 RISC II FPU Icache Dcache RISC II shrinks to 0 02 mm2 at 65 nm Caches via DRAM or 1 transistor SRAM Processor is the new transistor 1 22 2008 CS152 Spring 08 9 D j vu all over again Multiprocessors imminent in 1970s 80s 90s today s processors are nearing an impasse as technologies approach the speed of light David Mitchell The Transputer The Time Is Now 1989 Transputer was premature Custom multiprocessors tried to beat uniprocessors Procrastination rewarded 2X seq perf 1 5 years We are dedicating all of our future product development to multicore designs This is a sea change in computing Paul Otellini President Intel 2004 Difference is all microprocessor companies have switched to multiprocessors AMD Intel IBM Sun all new Apples 2 CPUs Procrastination penalized 2X sequential perf 5 yrs Biggest programming challenge from 1 to 2 CPUs 1 22 2008 CS152 Spring 08 10 Problems with Sea Change Algorithms Programming Languages Compilers Operating Systems Architectures Libraries not ready to supply Thread Level Parallelism or Data Level Parallelism for 1000 CPUs chip Architectures not ready for 1000 CPUs chip Unlike Instruction Level Parallelism cannot be solved by computer architects and compiler writers alone but also cannot be solved without participation of architects Need a reworking of all the abstraction layers in the computing system stack 1 22 2008 11 CS152 Spring 08 Abstraction Layers in Modern Systems Application Algorithm Programming Language Original domain of the computer architect 50s 80s Operating System Virtual Machines Instruction Set Architecture ISA Microarchitecture Gates Register Transfer Level RTL Circuits Devices Domain of recent computer architecture 90s Parallel computing security Reliability power Physics Reinvigoration of computer architecture mid 2000s onward 1 22 2008 CS152 Spring 08 12 The New CS152 New CS152 focuses on interaction of software and hardware more architecture and less digital engineering No FPGA design component We are preparing a separate FPGA design lab class for Fall 2008 where you can try building some of the architectural ideas we ll explore this semester 100 digital engineering Much of the material you ll learn this term was previously in CS252 Some of the current CS61C I first saw in CS252 nearly 20 years ago Maybe every 10 years shift CS252 CS152 CS61C Class contains labs based on various different machine designs Experiment with how architectural mechanisms work in practice on real software 1 22 2008 13 CS152 Spring 08 CS 152 Course Focus Understanding the design techniques machine structures technology factors evaluation methods that will determine the form of computers in 21st Century Technology Applications Programming Languages Computer Architecture Organization Hardware Software Boundary Operating Systems 1 22 2008 Parallelism Measurement Evaluation CS152 Spring 08 Interface Design ISA Compilers History 14 The New CS152 Executive Summary What you ll understand and experiment with in the new CS152 The processor your predecessors built in CS152 Plus the technology behind chip scale multiprocessors CMPs 1 22 2008 CS152 Spring 08 15 CS152 Administrivia Instructor Prof Krste Asanovic Office 645 Soda Hall krste eecs Office Hours M 1 3PM email to confirm 645 Soda Hall T A Henry Cook hcook eecs Office Hours TBD Lectures Tu Th 2 00 3 30PM 320 Soda Section W 10 00 11 00AM 2 Evans Text Computer Architecture A Quantitative Approach 4th Edition Oct 2006 Readings assigned from this edition don t use earlier Eds Web page http inst eecs berkeley edu cs152 Lectures available online before noon day of lecture 1 22 2008 CS152 Spring 08 16 CS152 Structure and Syllabus Approximately 7 modules
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