Overview - Computer Science & Engineering at WashUlu/cse467s/slides/icem.pdf · 37 ICEM Architecture • Deﬁnes three classes of drivers Virtualized Lock – provide only funconal

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KevinKlues,VladoHandziski,ChenyangLu,AdamWolisz,DavidCuller,DavidGay,andPhilipLevis

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Affilia&ons

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Overview

•  ConcurrencyControl:  ConcurrencyofI/OoperaFonsalone,notofthreadsingeneral  Synchronousvs.AsynchronousI/O

•  EnergyManagement:  PowerstateofdevicesneededtoperformI/OoperaFons

  DeterminedbypendingI/OrequestsusingAsynchronousI/O

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OS Flash Driver

Overview

Physical Flash

read()

write()

setPowerState()

Application

read() write() read() read()




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Overview

Themoreworkloadinforma&onanapplica&oncangivetheOS,themoreenergyit

cansavewhenschedulingthatworkload




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Outline

•  BackgroundInforma&on

•  PlaNormandApplicaFon•  Driverarchitecture•  EvaluaFon•  Conclusion

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Mo&va&on

•  DifficulttomanageenergyintradiFonalOSs HardtotellOSaboutfutureapplicaFonworkloads AlllogicpushedouttotheapplicaFon APIextensionsforhints?

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Exis&ngOSApproaches

•  DynamicCPUVoltageScaling VerFgo ‐ApplicaFonworkloadclasses GraceOS ‐Explicitreal‐Fmedeadlines

•  DiskSpinDown Coop‐IO ‐ApplicaFonspecifiedFmeouts

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Exis&ngOSApproaches

Savingenergyisacomplexprocess



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Exis&ngOSApproaches

SavingenergyisacomplexprocessAliCleapplica&onknowledgecanhelpusalot



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SensorNetworks

•  DomaininneedofuniquesoluFontothisproblem Harshenergyrequirements Verysmallsourceofpower(2AAbaWeries) MustrununaWendedfrommonthstoyears

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SensorNetworks

•  DomaininneedofuniquesoluFontothisproblem Harshenergyrequirements Verysmallsourceofpower(2AAbaWeries) MustrununaWendedfrommonthstoyears

•  FirstgeneraFonsensornetOSes(TinyOS,ConFki,ManFs,...) PushallenergymanagementtotheapplicaFon OpFmalenergysavingsatcostofapplicaFoncomplexity

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ICEM:IntegratedConcurrencyandEnergyManagement

•  AdevicedriverarchitecturethatautomaFcallymanagesenergy  ImplementedinTinyOS2.0‐‐alldriversfollowit

  IntroducesPowerLocks,split‐phaselockswithintegratedenergyandconfiguraFonmanagement

  Definesthreeclassesofdrivers:dedicated,shared,virtualized  Providesacomponentlibraryforbuildingdrivers

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ICEM:IntegratedConcurrencyandEnergyManagement

•  AdevicedriverarchitecturethatautomaFcallymanagesenergy  ImplementedinTinyOS2.0‐‐alldriversfollowit

  IntroducesPowerLocks,split‐phaselockswithintegratedenergyandconfiguraFonmanagement

  Definesthreeclassesofdrivers:dedicated,shared,virtualized  Providesacomponentlibraryforbuildingdrivers

•  AdvantagesofusingICEM  Energyefficient–Atleast98.4%ashand‐tunedimplementaFon

  Reducescodecomplexity–400vs.68linesofcode  EnablesnaturaldecomposiFonofapplicaFons

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Outline

•  IntroducFonandMoFvaFon

•  PlaHormandApplica&on•  ICEMarchitecture

•  EvaluaFon•  Conclusion

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TheTmotePlaHorm

•  SixmajorI/Odevices

•  PossibleConcurrency  I2C,SPI,ADC

•  EnergyManagement

 Turnperipheralsononlywhenneeded Turnoffotherwise

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Representa&veLoggingApplica&on

Every 12 hours: For all new entries: Send current sample Read next sample

Flash

Consumer

Sensors Radio

Every 5 minutes: Write prior samples Sample photo active Sample total solar Sample temperature Sample humidity

Producer

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Flash

Consumer

Sensors Radio


Producer

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Flash

Consumer

Sensors Radio


Producer

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Flash

Consumer

Sensors Radio


Producer

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Flash

Consumer

Sensors Radio


Producer

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Flash

Consumer

Sensors Radio


Producer

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Flash

Consumer

Sensors Radio


Producer

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Flash

Consumer

Sensors Radio


Producer

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Flash

Consumer

Sensors Radio


Producer

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CodeComplexity

Hand-Tuned Application

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CodeComplexity

Every 5 minutes: Turn on SPI bus Turn on flash chip Turn on voltage reference Turn on I2C bus Log prior readings Start humidity sample Wait 5ms for log Turn off flash chip Turn off SPI bus Wait 12ms for vref Turn on ADC Start total solar sample Wait 2ms for total solar Start photo active sample Wait 2ms for photo active Turn off ADC Turn off voltage reference Wait 34ms for humidity Start temperature sample Wait 220ms for temperature Turn off I2C bus


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CodeComplexity



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CodeComplexity



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CodeComplexity

Every 5 minutes: Log prior readings sample humidity sample total solar sample photo active sample temperature

ICEM Application Every 5 minutes: Turn on SPI bus Turn on flash chip Turn on voltage reference Turn on I2C bus Log prior readings Start humidity sample Wait 5ms for log Turn off flash chip Turn off SPI bus Wait 12ms for vref Turn on ADC Start total solar sample Wait 2ms for total solar Start photo active sample Wait 2ms for photo active Turn off ADC Turn off voltage reference Wait 34ms for humidity Start temperature sample Wait 220ms for temperature Turn off I2C bus


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Outline


•  PlaNormandApplicaFon•  ICEMarchitecture

•  EvaluaFon•  Conclusion

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Split‐PhaseI/OOpera&ons

•  Split‐phaseI/OoperaFons  Implementedwithinasinglethreadofcontrol

  ApplicaFonnoFfiedofI/OcompleFonthroughdirectupcall

  DrivergivenworkloadinformaFonbeforereturningcontrol

  Example:read()==>readDone()

Application

Driver

read() ()readDone ‏ ‏

I/O request I/O interrupt

void readDone(uint16_t val) { next_val = val; read(); }

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ICEMArchitecture

•  Definesthreeclassesofdrivers  Virtualized –provideonlyfuncFonalinterface

  Dedicated –providefuncFonalandpowerinterface  Shared –providefuncFonalandlockinterface

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VirtualizedDeviceDrivers

•  ProvideonlyaFunc&onalinterface•  AssumemulFpleusers•  Implicitconcurrencycontrolthroughbufferingrequests•  Implicitenergymanagementbasedonpendingrequests

•  Forhigher‐levelservicesthatcantoleratelongerlatencies

Energy: Implicit Concurrency: Implicit

Virtualized

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DedicatedDeviceDrivers

•  ProvideFunc&onalandPowerControlinterfaces•  Assumeasingleuser•  Noconcurrencycontrol•  Explicitenergymanagement

•  Low‐levelhardwareandboWom‐levelabstracFonshaveadedicateddriver

Energy: Implicit Concurrency: None

Dedicated

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SharedDeviceDrivers

•  ProvideFunc&onalandLockinterfaces•  AssumemulFpleusers

•  ExplicitconcurrencycontrolthroughLockrequest•  Implicitenergymanagementbasedonpendingrequests

•  UsedbyuserswithstringentFmingrequirements

Energy: Implicit Concurrency: Explicit

Shared

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ICEMArchitecture

•  Definesthreeclassesofdrivers Virtualized –provideonlyfuncFonalinterface

 Dedicated –providefuncFonalandpowerinterface  Shared –providefuncFonalandlockinterface

•  PowerLocks,split‐phaselockswithintegratedenergyandconfiguraFonmanagement

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PowerLocks

Dedicated Driver

Power Locks

Power Control

HW-Specific Configuration

Lock

Functional

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PowerLocks

Dedicated Driver

Power Locks

Power Control


Lock

Functional

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PowerLocks

Dedicated Driver

Power Locks

Power Control


Lock

Functional

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PowerLocks

Dedicated Driver

Power Locks

Power Control


Lock

Functional

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PowerLocks

Dedicated Driver

Power Locks

Power Control


Lock

Functional

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PowerLocks

Dedicated Driver

Power Locks

Power Control


Lock

Functional

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PowerLocks

Dedicated Driver

Power Locks

Power Control


Lock

Functional

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PowerLocks

Dedicated Driver

Power Locks

Power Control


Lock

Functional

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PowerLocks

Dedicated Driver

Power Locks

Power Control


Lock

Functional

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PowerLocks

Dedicated Driver

Power Locks

Power Control


Lock

Functional

1

2

3

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PowerLocks

Dedicated Driver

Power Locks

Power Control


Lock

Functional

Lock - - -

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PowerLocks

Dedicated Driver

Power Locks

Power Control


Lock

Functional

- - -

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PowerLocks

Dedicated Driver

Power Locks

Power Control


Lock

Functional

- - -

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ICEMArchitecture

•  Definesthreeclassesofdrivers Virtualized –provideonlyfuncFonalinterface

 Dedicated –providefuncFonalandpowerinterface  Shared –providefuncFonalandlockinterface

•  PowerLocks,split‐phaselockswithintegratedenergyandconfiguraFonmanagement

•  Componentlibrary

 Arbiters –manageI/Oconcurrency Configurators –setupdevicespecificconfiguraFons PowerManagers –provideautomaFcpowermanagement

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ComponentLibrary

Lock

Power Locks

Power Control


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ComponentLibrary

Lock

Power Control


Arbiter

Arbiter Configure

Default Owner

Configurator Power Manager

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ComponentLibrary

Power Control


Arbiter

Arbiter Configure

Default Owner


Lock

  Lockinterfaceforconcurrencycontrol(FCFS,Round‐Robin)

  ArbiterConfigureinterfaceautomaFchardwareconfiguraFon

  DefaultOwnerinterfaceforautomaFcpowermanagement

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ComponentLibrary

Power Control


Arbiter

Arbiter Configure

Default Owner


Lock

  Lockinterfaceforconcurrencycontrol(FCFS,Round‐Robin)

  ArbiterConfigureinterfaceautomaFchardwareconfiguraFon

  DefaultOwnerinterfaceforautomaFcpowermanagement

- - -

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ComponentLibrary

Power Control


Arbiter

Arbiter Configure

Default Owner


Lock

  ImplementArbiterConfigureinterface

  CallhardwarespecificconfiguraFonfromdedicateddriver

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ComponentLibrary

Power Control


Arbiter

Arbiter Configure

Default Owner


Lock

  ImplementDefaultOwnerinterface

  Powerdowndevicewhendevicefallsidle

  Powerupdevicewhennewlockrequestcomesin

  CurrentlyprovideImmediateandDeferredpolicies 58

SharedDriverExample

•  Msp430 USART (Serial Controller)  Three modes of operation – SPI, I2C, UART

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SharedDriverExample

Msp430 USART

• Msp430USART(SerialController) ThreemodesofoperaFon–SPI,I2C,UART

Power Control

Functional Configuration 60

SharedDriverExample

Arbiter

Immediate Power Manager

SPI User

Msp430 USART


SPI Configurator

Power Control

Functional Configuration

Lock

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Uart Configurator

SharedDriverExample


Arbiter

Immediate Power Manager

SPI User

Msp430 USART

SPI Configurator

Uart User

I2C User I2C Configurator

Power Control

Functional Configuration

Lock

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VirtualizedDriverExample

•  FlashStorage

Arbiter

Immediate Power Manager SPI User

Log User

Flash Driver

Log Virtualizer

Lock

Power Control

Functional

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•  FlashStorage

Arbiter


Log User

Flash Driver

Log Virtualizer

Lock

Power Control

Functional

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•  FlashStorage

Arbiter


Log User

Flash Driver

Log Virtualizer

Lock

Power Control

Functional

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•  FlashStorage

Arbiter


Log User

Flash Driver

Log Virtualizer

Lock

Power Control

Functional

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•  FlashStorage

Arbiter


Log User

Flash Driver

Log Virtualizer

Lock

Power Control

Functional

- - -

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•  FlashStorage

Arbiter


Log User

Flash Driver

Log Virtualizer

Lock

Power Control

Functional

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•  FlashStorage

Arbiter


Log User

Flash Driver

Log Virtualizer

Lock

Power Control

Block Virtualizer

Block User

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•  FlashStorage

Arbiter


Flash Driver Lock

Power Control

Log User

Log Virtualizer Block Virtualizer

Block User

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Outline


•  PlaNormandApplicaFon•  ICEMarchitecture

•  Evalua&on•  Conclusion

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Applica&ons

•  HandTuned –Mostenergyefficient

•  ICEM – All concurrentoperaFons•  Serial+ –OpFmalserialordering

•  Serial‐ –Worstcaseserialordering


Flash Consumer

Sensors Radio


Producer

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TmoteEnergyConsump&on

Average energy consumption for application operations

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TmoteEnergyConsump&on

Average energy consumption for application operations 74

Applica&onEnergyConsump&on

Application energy with 5 minute sampling interval and one send batch every 12 hours

0

25

50

75

100

288 Samples 2 Sends

E (

mA

s) Hand Tuned

ICEM

Serial +

Serial -

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0

25

50

75

100

288 Samples 2 Sends

E (

mA

s) Hand Tuned

ICEM

Serial +

Serial -

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0

25

50

75

100

288 Samples 2 Sends

E (

mA

s) Hand Tuned

ICEM

Serial +

Serial -

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SamplingPowerTrace

Overhead of ICEM to Hand-Tuned Implementation = ADC Timeout + Power Lock Overheads

With 288 samples per day ≈ 2.9 mAs/day ≈ 1049 mAs/year

Insignificant compared to total 5.60% of total sampling energy 0.03% of total application energy

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ExpectedNodeLife&mes

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Evalua&onConclusions

•  ConclusionsabouttheOS  SmallRAM/ROMoverhead  SmallcomputaFonaloverhead  EfficientlymanagesenergywhengivenenoughinformaFon

•  Conclusionsforthedeveloper  SelectrightpowerdownFmeouts  SubmitI/Orequestsinparallel

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Conclusion

•  ICEM: Integrated Concurrency and Energy Management   Device driver architecture for low power devices   At least 98.4% as energy efficient as hand-tuned

implementation of representative application   Simplifies application and driver development   Questions the assumption that applications must be responsible

for all energy management and cannot have a standardized OS with a simple API

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Ques&ons?

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Ques&ons?

•  SourceForgeTinyOSCVSrepository:  hWp://sourceforge.net/cvs/?group_id=28656

•  Librarycomponentsandinterfaces  Fnyos‐2.x/tos/interfaces  Fnyos‐2.x/tos/lib/power  Fnyos‐2.x/tos/system

•  ExampleDrivers  Atmega128ADC:tos/chips/atm128/adc  MTS300Photo:tos/sensorboards/mts300  MSP430USART0:tos/chips/msp430/usart  Storage:tos/chips/stm25p  CC2420:tos/chips/cc2420

Reading

•  K.Klues,V.Handziski,C.Lu,A.Wolisz,D.Culler,D.GayandP.Levis,IntegraFngConcurrencyControlandEnergyManagementinDeviceDrivers,ACMSymposiumonOperaFngSystemPrinciples(SOSP'07),October2007.

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Documents

Overview - Computer Science & Engineering at WashUlu/cse467s/slides/icem.pdf · 37 ICEM Architecture • Deﬁnes three classes of drivers Virtualized Lock – provide only funconal