cellular networks and mobile computing coms 6998-8, spring 2012

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Cellular Networks and Mobile Computing COMS 6998-8, Spring 2012. Instructor: Li Erran Li ( lel2139@columbia.edu ) http:// www.cs.columbia.edu /~coms6998-8 / 4 /2/ 2012: Mobile Cloud Computing. Mobile Cloud Computing ( mCloud ) today. Apple iCloud - PowerPoint PPT Presentation

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Cellular Networks and Mobile Computing COMS 6998-8, Spring 2012

Cellular Networks and Mobile ComputingCOMS 6998-8, Spring 2012Instructor: Li Erran Li (lel2139@columbia.edu)http://www.cs.columbia.edu/~coms6998-8/4/2/2012: Mobile Cloud Computing4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)11Mobile Cloud Computing (mCloud) todayApple iCloudStore content in cloud and sync to all registered devicesHosted by Windows Azure and Amazon AWSiCloud Storage APIs support third-party app document syncing2

4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)2Mobile Cloud Computing today (Contd)Amazon Silk browserAccelerates web accessLearns user behavior and precacheIntelligently partition work between local and Amazon cloud

3

4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)3mCloud Fundamental ChallengesWhat architecture best supports mCloud?What programming model best enables client to tap mCloud resources?What are basic services or building blocks for mCloud?What best supports service interaction?44/2/12Cellular Networks and Mobile Computing (COMS 6998-8)4mCloud ArchitectureResource-intensive mobile applicationsFace recognition for social networking appGesture recognition for control media app Object and post recognition for augmented reality appEnd-to-end latency and througput matters for crisp interactionAugmented reality need to display results within 1 secNeed high data rate processing capability, low frame rate can miss gesture5

Delay, loss on frame rate of video stream transfer [Odessa, 2011]4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)5mCloud Architecture (Contd)WAN performanceFirst hop latency in 3G is 200msVerizon LTE :128ms, 6.44 Mbps downlink, 5Mbps uplink [Pcworld, March 2011] There is a need for a middle tiercloudlet = (compute cluster+ wireless access point+ wired Internet access+ no battery limitations) data center in a box6Anatomizing Application Performance Differences on Smartphones, MobiSys 2010 (Huang et al)

4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)6mCloud Architecture (Contd)Cloudlet possible locationsCellular providers has a unique advantage7

BS

Wireless Core

Internet

WiFi APRDCA1RDCA2RDCB1RDCB2Regional Data centers (RDC)

RNC

Storage nodesComputenodesPossible locationsof cloudlet4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)7mCloud Programming ModelMAUI: RPC based offloading architectureCloneCloud: tight synchronization between cloud and phoneOdessa: data-flow graph to exploit parallelism in perception applicationsOrelans: a new programming model based on grainsMAUI, CloneCloud , Odessa all have profiler, solver8MAUICloneCloudOdessaOrleansRemote execution unitMethods (RMI)ThreadsTasksGrains4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)mCloud Programming Model: MAUICombine extensive profiling with an ILP solverMakes dynamic offload decisionsOptimize for energy reductionProfile: device, network, application

Leverage modern language runtime (.NET CLR)Portability: Mobile (ARM) vs Server (x86).NET Framework Common Intermediate LanguageType-Safety and Serialization: Automate state extractionReflection: Identifies methods with [Remoteable] tagAutomates generation of RPC stubs

94/2/12Cellular Networks and Mobile Computing (COMS 6998-8)9Maui serverSmartphoneApplicationClient ProxyProfilerSolverMaui RuntimeServer ProxyProfilerSolverMaui RuntimeApplicationRPCRPCMaui ControllermCloud Programming Model: MAUI (Contd)Intercepts Application CallsSynchronizes StateChooses local or remoteHandles ErrorsProvides runtime informationMAUI architecture

4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)10Source: MAUI Mobisys presentationthe MAUI coordinator, which handles authenticationand resource allocation for incoming requests to instantiate a partitionedapplication.10MAUI ProfilerProfilerCallgraphExecution TimeState sizeNetwork LatencyNetwork BandwidthDevice ProfileCPU CyclesNetwork Power CostNetwork DelayComputational Delay Computational Power CostComputational Delay

Annotated CallgraphSource: MAUI Mobisys presentation4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)1111MAUI SolverB900 mJ15ms

C5000 mJ3000 ms1000mJ25000 mJD15000 mJ12000 ms10000 mJ AComputation energy and delay for executionEnergy and delay for state transferA sample callgraphSource: MAUI Mobisys presentation4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)1212Is Global Program Analysis Needed?FindMatch900 mJ

InitializeFaceRecognizer5000 mJ1000mJ25000 mJDetectAndExtract Faces15000 mJ10000 mJUserInterface

Yes! This simple example from Face Recognition app shows why local analysis fails.Cheaper to do localSource: MAUI Mobisys presentation4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)1313Is Global Program Analysis Needed?FindMatch900 mJ

InitializeFaceRecognizer5000 mJ1000mJ25000 mJDetectAndExtract Faces15000 mJ10000 mJUserInterface

Yes! This simple example from Face Recognition app shows why local analysis fails.Cheaper to do localCheaper to do localSource: MAUI Mobisys presentation4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)1414Is Global Program Analysis Needed?FindMatch

InitializeFaceRecognizer1000mJDetectAndExtract FacesUserInterface

25900mJCheaper to offloadSource: MAUI Mobisys presentation4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)1515Can MAUI Adapt to Changing Conditions?Adapt to:Network Bandwidth/Latency ChangesVariability on methods computational requirements

Experiment:Modified off the shelf arcade game applicationPhysics Modeling (homing missiles)Evaluated under different latency settings

Source: MAUI Mobisys presentation4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)1616DoLevelHandleMissilesDoFrameHandleEnemiesHandleBonuses11KB + missiles11KB + missilesmissiles*Missiles take around 60 bytes each11KB + missilesRequired state is smallerComplexity increases with # of missilesCan MAUI Adapt to Changing Conditions?Source: MAUI Mobisys presentation4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)1717Case 1DoLevelHandleMissilesDoFrameHandleEnemiesHandleBonuses*Missiles take around 60 bytes eachZero MissilesLow latency (RTT < 10ms)

Computation cost is close to zeroOffload starting at DoLevelSource: MAUI Mobisys presentation4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)1818Case 2DoLevelHandleMissilesDoFrameHandleEnemiesHandleBonuses*Missiles take around 60 bytes each5 MissilesSome latency (RTT = 50ms)

Most of the computation costVery expensive to offload everythingLittle state to offloadOnly offload Handle MissilesSource: MAUI Mobisys presentation4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)1919MAUI ImplementationPlatformWindows Mobile 6.5.NET Framework 3.5HTC Fuze SmartphoneMonsoon power monitor

ApplicationsChessFace RecognitionArcade GameVoice-based translator

Source: MAUI Mobisys presentation4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)2020QuestionsHow much can MAUI reduce energy consumption?How much can MAUI improve performance?Can MAUI Run Resource-Intensive Applications?Source: MAUI Mobisys presentation4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)2121How much can MAUI reduce energy consumption?Big savings even on 3GAn order of magnitude improvement on Wi-FiFace RecognizerSource: MAUI Mobisys presentation4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)2222How much can MAUI improve performance?Improvement of around an order of magnitudeFace RecognizerSource: MAUI presentation4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)2323Latency to server impacts the opportunities for fine-grained offloadUp to 40% energy savings on Wi-FiSolver would decide not to offloadArcade GameSource: MAUI Mobisys presentation4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)2424Can MAUI Run Resource-Intensive Applications?CPU Intensive even on a Core 2 Duo PCCan be run on the phone with MAUITranslatorSource: MAUI Mobisys presentation4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)2525ConclusionsMAUI enables developers to:Bypass the resource limitations of handheld devicesLow barrier entry: simple program annotations

For a resource-intensive applicationMAUI reduced energy consumed by an order of magnitudeMAUI improved application performance similarly

MAUI adapts to:Changing network conditions Changing applications CPU demands

Source: MAUI Mobisys presentation4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)2626mCloud Programming Model: CloneCloudOffloading decision done at beginning of execution274/2/12Cellular Networks and Mobile Computing (COMS 6998-8)27The Before-After Picture

4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)28Courtesy: Byung-Gon Chun et. al. 28CloneCloud v1 Architecture

4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)29Courtesy: Byung-Gon Chun et. al. 29AppVM ClonesVirtual machine of entire client deviceAndroid x86 VM natively executed on VMWare in an x86 machine

Synchronized file systems

4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)30Courtesy: Byung-Gon Chun et. al. 30PartitioningWhere to partition code, satisfying any constraints for correctness, so as to optimize for current conditions4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)31Courtesy: Byung-Gon Chun et. al. 31Automatic Partitioning FrameworkPartition AnalyzerApplicationbinaryPartitioningconstraintsStatic analysislocation-constraintsProfilinginputsDynamicprofilingcost-annotatedexecutionsOptimizationsolverOptimal partitioningpointsIdentify valid split pointsConstruct cost modelsPick best choice for an objective4/2/12Cellular Networks and Mobile Computing (COMS 6998-8)32Courtesy: Byung-Gon Chun et.

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