DOP Center Student-Extensible and Scalable Time Triggered：DOP中心学生可扩展和可伸缩的时间触发

ExtensibleandScalableTimeTriggeredSchedulingfor

AutomotiveApplicationsWeiZhengAdvisor:ProfessorAlbertoSangiovanni-VincentelliAgendaMotivationProblemStatementPreviousWorkInvestigativeApproachMetricDefinitionMathematicalFormulationMulti-ObjectiveCostFunctionCaseStudySystemDescriptionCostFunctionEvaluationMetricsEvaluationConclusionFutureWorkProblemModelMathematicalModelImplementationAlgorithmEvaluationProjectMotivationHardReal-timeEmbeddedSystemsareubiquitouslyusedtodayinsafetycriticalcommercialapplicationsVerificationofcomplexsystemsistimeandresourceintensiveForfasttime-to-marketExtensibleandScalablesystemsPowerTransmissionUnit-6-linesperday-3000ppmresidentialdefects-5monthsvalidationtimeFABIOROMEO,Magneti-MarelliDAC,LasVegas,June20th,2001X-by-wireDesignFlowFunctionalModelSoftwareModelPhysicalArchitectureModelMappingControlalgorithmdesignPlantModeldesignFaultModelFunctionalSimulationAllocateFunctiontoTasksTaskandtheirWCETSignalsMiddlewareOSAllocatingtaskstoECUAllocatingsignalstoBUSECUarchitectureNetworkarchitectureSimulationcapturingcomputationalconstraintsTTbehavioralsimulationFunctionalityArchitectureSchedulingVirtualPrototypeRefinementINPUTPROCESSINGSYSTEMCOORDINATIONINPUTFAULTMANAGEMENTDISTRIBUTEDCONTROLAGREEMENTBY-WIRECONTROLNODESTATEOFHEALTHOUTPUTPROCESSINGOUTPUTFAULTMANAGEMENTTASKATASKCTASKATASKBTASKDSOURCE:GMFunctionality:AllocateFunctiontoTaskSystemArchitecture...ECUAPP.TTTASKSComm.controllerBUSDRIVEROSEKSCHEDULERBUSDRIVEROSEKTIMEDISPATCHERFT.TTTASKSAPP.OSEKTASKS......14012345681079111213STATICSEGDYNAMICSEGSYMBOLWINNITCOMMUNICATIONCYCLE14012345681079111213...AgendaProjectMotivationProblemStatementPreviousWorkInvestigativeApproachMetricDefinitionMathematicalFormulationMulti-ObjectiveCostFunctionCaseStudySystemDescriptionCostFunctionEvaluationMetricsEvaluationConclusionFutureWorkIdentifyasetofmetricstocaptureextensibilityandscalabilityApplythesetofmetricsinadesignEvaluatetheeffectivenessofthesetofmetricsSpecifically,wewantto:StudyahardrealtimeembeddedsystemsintheautomotivedomainFocusontheschedulingaspectofsystemdesignCharacterizeextensibilityandscalabilityinschedulingApplythesetofmetricsinaschedulingalgorithmEvaluatetheeffectivenessoftheapproachwithindustrialcasestudyIdentifyaSetofMetricsFormallyDescribeMetricApplyMetricsToDesignEvaluateResult.MetricsProblemProblemStatementAgendaProjectMotivationProblemStatementPreviousWorkInvestigativeApproachMetricDefinitionMathematicalFormulationMulti-ObjectiveCostFunctionCaseStudySystemDescriptionCostFunctionEvaluationMetricsEvaluationConclusionFutureWorkPreviousWork

StaticcyclicschedulinghasbeenextensivelyresearchedClassicalschedulingtheoryusemetricssuchasMinimizingsumofcompletiontimeMinimizingschedulelengthMinimizingresourceForrealtimesystems,deadlineisaddedasaconstraintEmphasisshiftedtofindingfeasiblesolutionswhileMinimizingend-to-enddelayMinimizingcommunicationcostClosestproblemconceptcomesfromPaulPop,etalClosestproblemformulationcomesfromArminBender,etalPreviousWork

PaulPop,etal,wroteaboutincrementaldesignUselistschedulingapproachtoobtainavalidscheduleUseaheuristictodistributeslackinthesystemMissingseveralimportantcomponents

PreemptionisnotconsideredResultingscheduleisnotsuitableforfuturetaskwithurgentdeadlineMessageslackisnotdistributedExtensibilityisnotconsideredArminBender,etal,usedmathematicalprogrammingformappingandschedulingWorkismotivatedbysoftware-hardwareco-designObjectiveistoobtainschedulefeasibilitywhileMaximizingPerformanceMinimizingresourceResearchDirectionFocusonoptimallyutilizeredundanciesinschedulesforextensibilityandscalabilityIdletimeandslacksaretraditionallyincorporatedinhardrealtimeembeddedsystemsschedulestoincreasesystemrobustnessWeshouldutilizetheseredundanciesto:TolerateincrementaldesignchangesAccommodatenewtaskstobeaddedinfutureproductupdatesD12_2D34D12_1T2_1T2_2T4T1_2T3T1_1Time01234BusECU2ECU1T5_1T5_2Idle[ECU1,T5_2]IdleTimeDataSlacksSlack[D12_2,T2_2]AgendaProjectMotivationProblemStatementPreviousWorkInvestigativeApproachMetricDefinitionMathematicalFormulationMulti-ObjectiveCostFunctionCaseStudySystemDescriptionCostFunctionEvaluationMetricsEvaluationConclusionFutureWorkExtensibilityMotivation

ToleratechangesofTaskWCETToleratechangesofDataWCTTImplementationMaintainBusSchedule

Maintainnon-involvedECU

schedules

MaintaininvolvedECU

scheduleswithoutreconfigurationApproach

Messageleft&RightslackMaxSumofallslacks

MinVarianceofallslacksScalability

AccommodateNEWtasksby

staticallyschedulingthemon

alegacysystem

Provideblocksofcomputation

timeforfuturecomputation

intensivetasks

Provideporosityinschedulesto

allowforfuturetaskswithtight

deadlinesECUidletimedistributionBusidletimedistributionEvenlydistributeallidle

timeModelCapturetheMetricsApplyingtheMetricsDevelopaformalrepresentationoftheproblemusingmathematicalprogrammingandsolveitusingexistingsolverModelingLanguage:AMPL

Advantage:obtainoptimalsolution

.costfunctionDisadvantage:computationallyintensive

suitableonlyformoderately

sizedproblemsAssumptions:HardrealtimedeadlinesStaticallyscheduledtaskswithdatadependencyDistributedandheterogeneousmulti-processorarchitectureTimetriggeredbuswithTDMAprotocolPreemptionallowedonECUswithnolevellimitsMulti-ratetasksupportwithadaptivetaskgraphexpansionFixedtaskallocationwithnotaskmigration

MathematicalModelMathematicalFormulation1Notations

ThesetofTasksThesetofECUThesetoftaskpairwithdatadependencyrunningonthesameECUThesetoftaskpairwithdatadependencyrunningondifferentECUThesetoftasknon-reachabletaskpairrunningonthesameECUThesetoftaskpairrunningonthesameECUThesetoftaskallocationforECUMathematicalModelMathematicalFormulation2

WCETReleaseTimePeriodIdletimeStartingtimeFinishingtimeTask:6-tupleparametervariableVector

WCTTLeftSlackRightSlackStartingtimeFinishingtime

Message:5-tupleparametervariableVector

ParametersandVariablesMappingfromTaskstoECUsTaskandMessageiftaskiismappedtoECUjotherwiseMathematicalModelMathematicalFormulation3ifthestartingtimeoftaskiprecedethestartingtimeoftaskjotherwiseiftaskiisnotpreemptedbytaskjotherwiseParametersandVariables(continue)IdletimeandIntegerVariablesifdatatransmittedfromtaskitotaskjprecedesdatatransmittedfromtaskktolotherwiseIdletimefortaski,ifiisnotthefirsttaskinofitsrunningECUFirstidletimeforeachECUkIdletimeforECUkbeforethesuperperiodMathematicalModelMathematicalFormulation4Subjecttothefollowingconstraints:ReleaseandDeadlineConstraints

ExecutionTime/TransmissionConstraintsPrecedenceConstraintsNon-negativeandIntegerConstraintsMathematicalModelMathematicalFormulation5Constraints(continued):MutualexclusionconstraintsIdletimeconstraintsMathematicalModelAgendaProjectMotivationProblemStatementPreviousWorkInvestigativeApproachMetricDefinitionMathematicalFormulationMulti-ObjectiveCostFunctionCaseStudySystemDescriptionCostFunctionEvaluationMetricsEvaluationConclusionFutureWorkMultipleObjectiveCostFunctionExtensibility

ScalabilityJointlyExtensibility&ScalabilityAlgorithmD34T5_2D12_2T2_2T1_2T4T5_1T3T2_1T1_1Time01234BusECU2ECU1D12_1ExtensibleScheduleWCETChangesWCETIncreaseT6D34D12_2T2_2T1_2T4T3T2_1T1_1T5_1D12_1Time01234BusECU2ECU1ScalableSchedule:AddNewTaskT5_2T2_2D12_2T1_2T5_2T4T3D12_1T2_1T1_1Time01234BusECU2ECU1T5_1D34MinimizeEndtoEndLatencyTaskgraphexpansion(inaSUPERperiod)T1T4T3functionalityECU2ECU1FlexRayarchitectureMappingT5T1T3T2T1T2T4T5T5T2_2D12_2T5_2D34T4T3D12_1T2_1T1_1Time01234BusECU2ECU1T5_1T1_2CheckingSchedulabilityD34D12_2T2_2T1_2T4T3T2_1T1_1Time01234BusECU2ECU1T5_1T5_2D12_1ScalableScheduleT6T2D34T5_2D12_2T2_2T1_2T4T5_1T3T2_1T1_1Time01234BusECU2ECU1D12_1ExtensibleScheduleD34D12_2T2_2T4T1_2T2_1D12_1T3T1_1Time01234BusECU2ECU1T5_1T5_2JointlyConsideringExtensible

andScalableAlgorithmExtensibilityandScalabilityofTimeTriggeredScheduling

AgendaProjectMotivationProblemStatementPreviousWorkInvestigativeApproachMetricDefinitionMathematicalFormulationMulti-ObjectiveCostFunctionCaseStudySystemDescriptionCostFunctionEvaluationMetricsEvaluationSummaryConclusionFutureWorkAdvancedAutomotiveControlApplicationDesiredSpeedCurrentSpeedObjectDistanceandSpeedCurrentthrottlepositionDesiredbrakingforceDesiredThrottlepositionActuatebrakesActuateThrottleLeft-RearWheelspeedActuateThrottleActuateBrakeDesiredBrakingForceLateralaccelerationHand-wheelpositionYawRateRight-FrontWheelSpeedRight-RearWheelSpeedLeft-FrontWheelSpeedRoad-wheelforceHand-wheelpositionDesiredhand-WheeleffortDesiredroad-WheelangleForcefeedbackTodriverActuatesteeringRackmotorT10T14T12T13T11T8T7T9T24T23T22T21T19T20T18T17T16T15T2T6T5T4T3T1ApplicationsandcorrespondingtaskgraphrepresentationsAdaptiveCruiseControlTractionControlElectricPowerSteeringArchitectureandTaskAllocationP1T4,T11P3T10,T20P2T3,T12,T22FlexRayThrottlepositionSteeringRackForceObjectDistanceBrakeThrottleValueHand-WheelmotorSteeringRackMotorAccel-aratorHand-WheelangleCarSpeedRFWheelSpeedRRWheelSpeedLFWheelSpeedLRWheelspeedProcessorswithtasksallocatedcSensorsaredirectlyconnectedtothebusActuatorsaredirectlyconnectedtothebusImplementationDescribetheMetricsFormalizetheMetricsGetSchedulingResultEvaluateResult.MetricsCasestudyAutomaticAMPLdatafilegenerationAMPLmodelwithcostfunctionandconstraintsCPLEXsolverAutomaticGantgraphgenerationT2_2D12_2T1_2T5_2T4T3D12_1T2_1T1_1Time01234BusECU2ECU1T5_1D34.Self-developedprojectinfrastructure.Off-the-shelf

projectinfrastructureImplementationInfrastructureAgendaProjectMotivationProblemStatementPreviousWorkInvestigativeApproachMetricDefinitionMathematicalFormulationMulti-ObjectiveCostFunctionCaseStudySystemDescriptionCostFunctionEvaluationMetricsEvaluationSummaryConclusionFutureWorkCostFunctionEvaluationMulti-objectivecostfunctionisanabstractionMathematicalprogrammingformulationhaslimitedsemanticsExtensibilityandscalabilitymetricsaretoocomplexDescribedinfull,thecostfunctionwouldbetoocomputationallyexpensiveMustdetermineifthecostfunctionabstractioneffectivelyrepresentsthemetricsUsetheresultsofCPLEXsolverExtractrealslackandidletimedistributionsbasedonprecisedefinitionofthemetricsCompareresultswiththeschedulewithoutextensibilityandscalabilityoptimizationEvaluationTraditionalSchedulingResultOptimizingforEndtoEndLatencyEvaluationOptimizedSchedulingResultOptimizingforExtensibilityandScalabilityEvaluationMetricsEvaluationOursetofmetricsisoneabstractionoftheextensibilityandscalabilityconceptMustdetermineifourmetricseffectivelyhandlesincrementaldesignchangesIncrementalDesignScenario:BasicACCStop-N-GoACCAdditionofanewAdaptiveCruiseControlfeaturePredictdesiredspeedbasedon:DigitalmapinformationForwardlookingvisionsensorRequiresadditionoftasksandmessagesSomeexistingtaskswillneedmorecomputationtimeEvaluationAdaptiveCruiseControlIncrementalDesignChanges:AddnewDigitalMapComputationtaskonP1MorecomplexalgorithminT10(DesiredSpeedControl)DesiredSpeedControlrequiresnewinputfromHandWheelSensorDesiredThrottleControlrequiresnewinputfromForwardVisionSensorEvaluationT10T14T12T13T11T8T7T9T_addT19DesiredSpeedCurrentSpeedObjectDistanceandSpeedCurrentthrottlepositionDesiredbrakingforceDesiredThrottlepositionActuatebrakesActuateThrottleDigitalMap

ComputationHandWheel

PositionTraditionalScheduleInTraditionSchedule:IncrementalchangesimpossiblewithoutfullreschedulingEvaluationOptimizedScheduleInTraditionSchedule:IncrementalchangesimpossiblewithoutfullreschedulingInOptimizedSchedule:AlotmoreporositytoaccommodatenewtasksandmessagesEvaluationOptimizedScheduleInTraditionSchedule:IncrementalchangesimpossiblewithoutfullreschedulingInOptimizedSchedule:AlotmoreporositytoaccommodatenewtasksandmessagesNewfunctionsadded:

WithoutdisturbinglegacyschedulesEvaluationAgendaProjectMotivationProblemStatementPreviousWorkInvestigativeApproachMetricDefinitionMathematicalFormulationMulti-ObjectiveCostFunctionCaseStudySystemDescriptionCostFunctionEvaluationMetricsEvaluationConclusionFutureWorkConclusionSuccessfullycapturedextensibilityandscalabilitymetricsRecognizedimplicationsinacceleratingtime-to-marketofembeddedsystemdevelopmentReducere-verificationburdeninincrementaldesignflowNoincreaseinresourcerequirementsFormulatedtheschedulingproblemasamathematicalprogrammingproblemConstructedmulti-objectcostfunctionsabstractedfromthemetricsThecostfunctionisshowntobeeffectiveforthemetricsThemetricsisshowntobeeffectiveinindustrycasestudyAgendaProjectMotivationProblemStatementPreviousWorkInvestigativeApproachMetricDefinitionMathematicalFormulationMulti-ObjectiveCostFunctionCaseStudySystemDescriptionCostFunctionEvaluationMetricsEvaluationConclusionFutureWorkFutureWorkProtocolComparisonFlexRayVs.TTPSlotSizeOptimization...14012345681079111213......6012435...COMMUNICATIONCYCLECOMMUNICATIONCYCLESlotSizeExplorationRead/Write