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Unformatted text preview: CIS 501 (Martin): Technology & Energy 1 CIS 501 Computer Architecture Unit 3: Technology & Energy Slides developed by Milo Martin & Amir Roth at the University of Pennsylvania with sources that included University of Wisconsin slides by Mark Hill, Guri Sohi, Jim Smith, and David Wood. CIS 501 (Martin): Technology & Energy 2 This Unit Technology basis Transistors & wires Cost & fabrication Implications of transistor scaling (Moores Law) Energy & power CIS 501 (Martin): Technology & Energy 3 Readings MA:FSPTCM Section 1.1 (technology) Section 9.1 (power & energy) Paper G. Moore, Cramming More Components onto Integrated Circuits T. Mudge, Power: a first-class architectural design constraint CIS 501 (Martin): Technology & Energy 4 Review: Simple Datapath How are instruction executed? Fetch instruction (Program counter into instruction memory) Read registers Calculate values (adds, subtracts, address generation, etc.) Access memory (optional) Calculate next program counter (PC) Repeat Clock period = longest delay through datapath PC Insn Mem Register File s1 s2 d Data Mem + 4 Recall: Processor Performance Programs consist of simple operations (instructions) Add two numbers, fetch data value from memory, etc. Program runtime = seconds per program = (instructions/program) * (cycles/instruction) * (seconds/cycle) Instructions per program : dynamic instruction count Runtime count of instructions executed by the program Determined by program, compiler, instruction set architecture (ISA) Cycles per instruction : CPI (typical range: 2 to 0.5) On average, how many cycles does an instruction take to execute? Determined by program, compiler, ISA, micro-architecture Seconds per cycle : clock period, length of each cycle Inverse metric: cycles per second (Hertz) or cycles per ns (Ghz) Determined by micro-architecture, technology parameters This unit: transistors & semiconductor technology CIS 501 (Martin): Technology & Energy 5 CIS 501 (Martin): Technology & Energy 6 Semiconductor Technology Basic technology element: MOSFET Solid-state component acts like electrical switch MOS : metal-oxide-semiconductor Conductor, insulator, semi-conductor FET : field-effect transistor Channel conducts source ! drain only when voltage applied to gate Channel length : characteristic parameter (short ! fast) Aka feature size or technology Currently: 0.032 micron ( m), 32 nanometers (nm) Continued miniaturization (scaling) known as Moores Law Wont last forever, physical limits approaching (or are they?) channel source drain insulator gate Substrate channel source drain gate CIS 501 (Martin): Technology & Energy 7 Transistors and Wires IBM From slides Krste Asanovi ! , MIT Fabrication & Cost CIS 501 (Martin): Technology & Energy 8 CIS 501 (Martin): Technology & Energy...
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- Fall '08
- Computer Architecture