CS152 Computer Architecture and Engineering Lecture 4 Cost and Design Feb 3 1999 John Kubiatowicz http cs berkeley edu kubitron lecture slides http www inst eecs berkeley edu cs152 2 3 99 UCB Spring 1999 CS152 Kubiatowicz Review Performance and Technology Trends Performance 1000 Supercomputers 100 Mainframes 10 Minicomputers Microprocessors 1 0 1 1965 1970 1975 1980 1985 Year 1990 1995 2000 Technology Power 1 2 x 1 2 x 1 2 1 7 x year Feature Size shrinks 10 yr Switching speed improves 1 2 yr Density improves 1 2x yr Die Area 1 2x yr RISC lesson is to keep the ISA as simple as possible 2 3 99 Shorter design cycle fully exploit the advancing technology 3yr Advanced branch prediction and pipeline techniques Bigger and more sophisticated CS152 Kubiatowicz on chip UCB Spring 1999 caches Review Technology Logic Design and Delay CMOS Technology Trends Complementary PMOS and NMOS transistors CMOS inverter and CMOS logic gates Delay Modeling and Gate Characterization Delay Internal Delay Load Dependent Delay x Output Load Clocking Methodology and Timing Considerations Simplest clocking methodology All storage elements use the SAME clock edge Cycle Time CLK to Q Longest Delay Path Setup Clock Skew CLK to Q Shortest Delay Path Clock Skew Hold Time 2 3 99 UCB Spring 1999 CS152 Kubiatowicz Overview Cost and Design Review from Last Lecture 2 minutes Cost and Price 18 Administrative Matters 3 minutes Design process 27 minutes Break 5 minutes More Design process 15 minutes Online notebook 10 minutes 2 3 99 UCB Spring 1999 CS152 Kubiatowicz Integrated Circuit Costs Die cost Wafer cost Dies per Wafer Die yield Dies per wafer Wafer diam 2 2 Wafer diam Test dies Wafer Area Die Area 2 Die Area Die Area Die Yield Wafer yield 1 Defects per unit area Die Area Die Cost is goes roughly with the cube of the area 2 3 99 UCB Spring 1999 CS152 Kubiatowicz Die Yield Raw Dice Per Wafer wafer diameter 6 15cm 8 20cm 10 25cm die area mm2 100 144 196 139 90 62 265 177 124 431 290 206 256 44 90 153 324 32 68 116 400 23 52 90 die yield 23 19 16 12 11 10 typical CMOS process 2 wafer yield 90 defect density 2 cm2 4 test sites wafer 6 15cm 8 20cm 10 25cm Good Dice Per Wafer Before Testing 31 16 9 5 3 59 32 19 11 7 96 53 32 20 13 2 5 9 typical cost of an 8 4 metal layers 0 5um CMOS wafer 2000 2 3 99 UCB Spring 1999 CS152 Kubiatowicz Real World Examples Chip MetalLineWaferDefect AreaDies YieldDie Cost layers widthcost cm2 mm2wafer 386DX 2 0 90 900 1 0 486DX2 43 360 71 4 30 80 1200 1 0 81 181 54 12 PowerPC 601 40 80 1700 1 3 121 115 28 53 HP PA 7100 30 80 1300 1 0 196 66 27 73 DEC Alpha 30 70 1500 1 2 234 53 19 149 SuperSPARC 30 70 1700 1 6 256 48 13 272 Pentium 296 40 9 417 30 80 1500 1 5 From Estimating IC Manufacturing Costs by Linley Gwennap Microprocessor Report August 2 1993 p 15 2 3 99 UCB Spring 1999 CS152 Kubiatowicz Other Costs IC cost Die cost Testing cost Packaging cost Final test yield Packaging Cost depends on pins heat dissipation Chip 386DX 486DX2 PowerPC 601 HP PA 7100 DEC Alpha SuperSPARC Pentium 2 3 99 Die cost 4 12 53 73 149 272 417 Package pins type 132 QFP 168 PGA 304 QFP 504 PGA 431 PGA 293 PGA 273 PGA cost 1 11 3 35 30 20 19 UCB Spring 1999 Test Assembly 4 12 21 16 23 34 37 Total 9 35 77 124 202 326 473 CS152 Kubiatowicz System Cost 1995 96 Workstation System Subsystem of total cost Cabinet Sheet metal plastic1 Power supply fans 2 Cables nuts bolts 1 Subtotal 4 Motherboard Processor6 DRAM 64MB 36 Video system 14 I O system 3 Printed Circuit board 1 Subtotal 60 I O Devices Keyboard mouse1 Monitor 22 Hard disk 1 GB 7 Tape drive DAT 6 Subtotal 36 2 3 99 UCB Spring 1999 CS152 Kubiatowicz Cost vs Price Q What of company income on Research and Development R D 50 80 Average Discount 33 45 gross margin 33 14 direct costs direct costs 8 10 component cost component cost 25 31 avg selling price 25 100 Gross Margin 33 Direct Costs Component Cost Input chips displays 2 3 99 component cost Making it labor scrap returns WS PC list price Overhead R D rent marketing profits UCB Spring 1999 Commision channel profit volume discounts CS152 Kubiatowicz Cost Summary Integrated circuits driving computer industry Die costs goes up with the cube of die area Economics is the ultimate driver for performance 2 3 99 UCB Spring 1999 CS152 Kubiatowicz Administrative Matters Review complete did ok on prob 1 4 Problems 2 and 3 more challenging Make sure you look at solutions Read Chapter 4 ALU Multiply Divide FP Mult Dollars for bugs First to report bug gets 1 check Send 1 bug email to mkp mkp com Include page number orginal text why bug fixed text 2 3 99 UCB Spring 1999 CS152 Kubiatowicz The Design Process To Design Is To Represent Design activity yields description representation of an object Traditional craftsman does not distinguish between the conceptualization and the artifact Separation comes about because of complexity The concept is captured in one or more representation languages This process IS design Design Begins With Requirements Functional Capabilities what it will do Performance Characteristics Speed Power Area Cost 2 3 99 UCB Spring 1999 CS152 Kubiatowicz Design Process cont CPU Design Finishes As Assembly Design understood in terms of components and how they have been assembled Datapath ALU Top Down decomposition of complex functions behaviors into more primitive functions Regs Control Shifter Nand Gate bottom up composition of primitive building blocks into more complex assemblies Design is a creative process not a simple method 2 3 99 UCB Spring 1999 CS152 Kubiatowicz Design Refinement Informal System Requirement Initial Specification Intermediate Specification refinement increasing level of detail Final Architectural Description Intermediate Specification of Implementation Final Internal Specification Physical Implementation 2 3 99 UCB Spring 1999 CS152 Kubiatowicz Design as Search Problem A Strategy 1 SubProb 1 BB1 BB2 Strategy 2 SubProb2 SubProb3 BB3 BBn Design involves educated guesses and verification Given the goals how should these be prioritized Given alternative design pieces which should be selected Given design space of components assemblies which part will yield the best solution Feasible good choices vs Optimal choices 2 3 99 UCB Spring 1999 CS152 Kubiatowicz Problem Design a fast ALU for the MIPS ISA Requirements Must support the Arithmetic Logic operations Tradeoffs of cost and speed based on frequency of occurrence hardware budget 2 3 99 UCB Spring 1999 CS152 Kubiatowicz MIPS ALU requirements
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