1EECS 150 - Components and Design Techniques for Digital SystemsLec 24 –Power, Power, Power11/27/2007David CullerElectrical Engineering and Computer SciencesUniversity of California, Berkeleyhttp://www.eecs.berkeley.edu/~cullerhttp://inst.eecs.berkeley.edu/~cs1502Broad Technology TrendsToday: 1 million transistors per $Moore’s Law: # transistors on cost-effective chip doubles every 18 monthsMote!yearsComputersPer Person103:11:106LaptopPDAMainframeMiniWorkstationPCCell1:11:103Bell’s Law: a new computer class emerges every 10 yearsSame fabrication technology provides CMOS radios for communication and micro-sensors3Sustaining Moore’s Law“If unchecked, the increasing power requirements of computer chips could boost heat generation to absurdly high levels,” said Patrick Gelsinger, Intel’s CTO is reported to have said.“By mid-decade, that Pentium PC may need the power of a nuclear reactor. By the end of the decade, you might as well be feeling a rocket nozzle than touching a chip. And soon after 2010, PC chips could feel like the bubbly hot surface of the sun itself,”4Power, Power, Power• IT devices represent 2% of global CO2 emissions worldwideyearsComputersPer Person103:11:106LaptopPDAMainframeMiniWorkstationPCCell1:11:103Mote!Mobile telecom, 9%LAN and office telecom, 7%Fixed-line Telecom, 15%Printers, 6%Servers, 23%PCs and Monitors, 39%Source Gartner5What is EECS150 about?Transfer FunctionTransistor PhysicsDevicesGatesCircuitsFlipFlopsEE 40HDLMachine OrganizationInstruction Set ArchPgm Language Asm / Machine LangCS 61CDeep Digital Design ExperienceFundamentals of Boolean LogicSynchronous CircuitsFinite State MachinesTiming & ClockingDevice Technology & ImplicationsController DesignArithmetic UnitsBus DesignEncoding, FramingTesting, DebuggingHardware ArchitectureHDL, Design Flow (CAD)6Data Centers• 1.5% of total US energy consumption in 2006• 60 Billion kWh• Doubled in past 5 years and expected to double in next 5 to 100 Billion kWh– 7.4 B$ annuallyEPA report aug 4 2007 delivered to congress in response to public law 109-431ClientyearsComputersPer Person103:11:106LaptopPDAMainframeMiniWorkstationPCCell1:11:103Mote!48% of IT budget spent on energy50% of data center power goes into cooling1 MW DC => 177 M kwH + 60 M gals water + 145 K lbs copper + 21 k lbs lead7Servers: Total Cost of Ownership (TCO)Machine rooms are expensive …removing heat dictates how many servers can fitElectric bill adds up! Powering the servers + powering the air conditioners is a big part of TCOReliability: running computers hot makes them fail more often8M. K. Patterson, A. Pratt, P. Kumar, “From UPS to Silicon: an end-to-end evaluation of datacenter efficiency”, Intel Corporation9+1V-1 Ohm Resistor1A0.24 Calories per SecondHeats 1 gram of water 0.24 degree CThis is how electric tea pots work ...1 Joule of Heat Energy per Second1 Watt20 W rating: Maximum power the package is able to transfer to the air. Exceed rating and resistor burns.P watts = I amps * V volts10Basics• Warning! In everyday language, the term “power” is used incorrectly in place of “energy”• Power is not energy– E = P * T• Power is not something you can run out of• Power can not be lost or used up• It is not a thing, it is merely a rate• It can not be put into a battery any more than velocity can be put in the gas tank of a car11Data Center Power Usage Today12PC• HPxw4200– 180 w active with two LCDs– 130 w w/o monitor, 110 w idle, – 6 w suspend• 60% are left on around the clock• 15% of all office power• US: – 1.72 B$ & 15 M tons CO2annually• Mid size company:– 165 K$ & 1400 tons of CO2• Existing power mgmt (hibernation) can reduce by 80%=> Do nothing wellPC Energy Report 2007, 1EClientEnterpriseServerJ2EESOAPyearsComputersPer Person103:11:106LaptopPDAMainframeMiniWorkstationPCCell1:11:103Mote!13Do Nothing Well14Notebooks ... now most of the PC marketPerformance: Must be “close enough” to desktop performance ... many people no longer own a desktopHeat: No longer “laptops” -- top may get “warm”, bottom “hot”. Quiet fans OKSize and Weight: Ideal: paper notebook1 in8.9 in12.8 inApple MacBook -- Weighs 5.2 lbs15Battery: Set by size and weight limits ...Almost full 1 inch depth. Width and height set by available space, weight.Battery rating: 55 W-hourAt 2.3 GHz, Intel Core Duo CPU consumes 31 W running a heavy load - under 2 hours battery life! And, just for CPU!At 1 GHz, CPU consumes 13 Watts. “Energy saver”option uses this mode ...46x energy than iPod nano. iPod lets you listen to music for 14 hours!16Battery Technology• Battery technology has developed slowly• Li-Ion and NiMh still the dominate technologies• Batteries still contribute significantly to the weight of mobile devicesToshiba Portege3110 laptop - 20%Handspring PDA - 10%Nokia 61xx -33%1755 W-hour battery stores the energy of 1/2 a stick of dynamite.If battery short-circuits, catastrophe is possible ...18CPU Only Part of Power Budget2004-era notebook running a full workload.If our CPU took no power at all to run, that would only double battery life!CPULCD Backlight“other”LCDGPU19Automobiles700 MillionTelephones4 BillionElectronic Chips60 BillionX-Internet“X-Internet” Beyond the PCForrester Research, May 2001Revised 2007500Million1.5 BillionInternet ComputersInternet UsersToday’s Internet20“X-Internet” Beyond the PCForrester Research, May 20010500010000150002001200220032004200520062007200820092010MillionsYearXInternetPCInternet21Cooling an iPod nano ...Like a resistor, iPod relies on passive transfer of heat from case to the airWhy? Users don’t want fans in their pocket ... To stay “cool to the touch” via passive cooling, power budget of 5 WIf iPod nano used 5W all the time, its battery would last 15 minutes ...22Powering an iPod nano (2005 edition)Battery has 1.2 W-hour rating: Can supply 1.2 W of power for 1 hour1.2 W / 5 W = 15 minutesReal specs for iPod nano : 14 hours for music, 4 hours for slide shows85 mW for music300 mW for slidesMore W-hours require bigger battery and thus bigger “form factor” --it wouldn’t be “nano” anymore!230.55 ounces12 hour battery life$79.001 GB2412 hour battery life24 hour battery life for audio5 hour battery life for photos20 hour battery life for audio, 6.5 hours for movies (80GB version)Up from 14 hours for 2005 iPod nanoUp from 4 hours for 2005 iPod nanoThinner than 2005 iPod nano25What’s in the
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