Dealing with AADL End-to-end Flow Latency in UML MARTE

AOSTE INRIA/I3SSophia Antipolis, France

S-Y. Lee, F. Mallet, R. de Simone

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Motivation Allocation of heterogeneous applications on to

heterogeneous execution platforms The execution platform may be speculative (Y-chart) May explore several platforms for a single application

Early analysis (end-to-end flow latency) requires Combined models of the applications, execution

platforms AND of the allocation AADL and MARTE have this ability

MARTE is more general Some specific AADL constructs require a special

attention to find equivalences in MARTE

IntroductionIntroduction AADL MARTE for AADL Conclusion

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AADL

Architecture Analysis & Design Language Avionics/Automotive standard from Society of

Automotive Engineers. Design & Analysis of performance-critical RT systems

Application/Software Components Thread, Thread Group, Process, Subprogram

Execution Platform Components Bus, Device, Processor, Memory

Binding Bind Application onto Execution Platform

IntroductionIntroduction AADL MARTE for AADL Conclusion

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MARTE OMG UML2 Profile for Modeling and Analysis of

Real-Time and Embedded systems OMG Adopted Specification (ptc/07-08-04) => FTF

Time Define a Timed Causality Model for UML Broad enough to cover several Models of Computation

(exercise: Model AADL MoCC) Allocation sub-profiles

Describe various possible allocations (and their costs) Time analysis needs to cope with communication costs

and context switching costs, etc.

IntroductionIntroduction AADL MARTE for AADL Conclusion

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MARTE OMG UML2 Profile for Modeling and Analysis of

Real-Time and Embedded systems OMG Adopted Specification (ptc/07-08-04) => FTF

Time Define a Timed Causality Model for UML Broad enough to cover several Models of Computation

(exercise: Model AADL MoCC) Allocation sub-profiles

Describe various possible allocations (and their costs) Time analysis needs to cope with communication costs

and context switching costs, etc.

IntroductionIntroduction AADL MARTE for AADL Conclusion

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Our contribution

How to represent, in MARTE, AADL constructs amenable to end-to-end flow latency analysis ? Address examples from Feiler & Hansson

(Technical Note CMU/SEI-2007-TN-010, June 2007)

Previous contribution on immediate/delayed data communications (Embedded Systems Specification and Design Languages, chapter 11, Springer, March 2008)

Today, focus on How to mix data-driven and event-based communications Lots of applications in automotive with protocols like

FlexRay

IntroductionIntroduction AADL MARTE for AADL Conclusion

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An example in AADLExecutionPlatform

Device (sensor)ExecutionPlatformDevice (actuator)

SoftwareThread

Event-data port (message-passing, queues)

Event port (queues)

Data port (no queue)

SoftwarePeriodic Thread

Delayed communication immediate

Mix of Execution Platform and Software Case-based definition of the underlying Model of Computation and Communication (MoCC)

Introduction AADLAADL MARTE for AADL Conclusion

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Delayed Communications

Latched communication: classical in EDA

T1

T2

f1=q1*ff2=q2*f

Introduction AADLAADL MARTE for AADL Conclusion

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Immediate Communications

Instantaneous communications

T1

T2

f1=q1*ff2=q2*f

Introduction AADLAADL MARTE for AADL Conclusion

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Causality problems

To be deterministic, one must Perform clock computations Define a schedule Compute a Fix-point

How to deal with the causality problems ? Synchronous languages !

Introduction AADLAADL MARTE for AADL Conclusion

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A simple sketch hides a complex model

Most of the model is hidden as text in AADL

Introduction AADLAADL MARTE for AADL Conclusion

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Summary of Issues (and solutions) Mix of Execution Platform and Software

Separate them, use Allocation to associate costs Case-based definition of the underlying Model of

Computation and Communication (MoCC) Make It Explicit

Do not deal with the causality problems Use well-known solutions … from synchronous languages

Most of the model is hidden as text Make the time a first-class citizen

Introduction AADLAADL MARTE for AADL Conclusion

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UML and MARTE Application (pure causal/untimed relations)

UML Activity Diagrams

Different queuing policies (event, event-data, data) ?

With queues (event or event-data)and selection policy if needed (All Items?)

Without queues (data)

Introduction AADL MARTE for AADLMARTE for AADL Conclusion

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UML and MARTE Software Resources (OS, middleware, …)

UML Composite Structure Diagrams

MARTE Library for AADL

Introduction AADL MARTE for AADLMARTE for AADL Conclusion

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UML and MARTE Execution platform

Composite Structure Diagrams

MARTE Library for AADL

Introduction AADL MARTE for AADLMARTE for AADL Conclusion

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Allocation in MARTEIntroduction AADL MARTE for AADLMARTE for AADL Conclusion

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MoCCs with MARTE Overall only two different kinds of communications

in AADL Dataflow

Event-data ports + Aperiodic threads Data ports + immediateperiodic threads

t1.finish alternatesWith t2.start

Introduction AADL MARTE for AADLMARTE for AADL Conclusion

T1

T2

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MoCCs with MARTE Overall only two different kinds of communications

in AADL Sampled

Data ports + Delayed + Periodic threads Data ports + immediatePeriodic (oversampling) threads

Introduction AADL MARTE for AADLMARTE for AADL Conclusion

T1

T2t2.start = t1.finish sampledTo ^t2

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Clock Constraint Specification LanguageIntroduction AADL MARTE for AADLMARTE for AADL Conclusion

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Timing analysis resultsUML Timing Diagrams

Introduction AADL MARTE for AADLMARTE for AADL Conclusion

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Conclusion

MARTE is under finalization by FTF MARTE annex A

Guidelines about AADL and East-ADL2 (AutoSAR) MARTE as a language to support MoCC definition

Give a Timed Causality Model to UML AADL may benefit from using MARTE as a front-

end Reuse all existing UML tools with support teams MARTE may require some adaptations to ease the

work of designers used to AADL

Introduction AADL MARTE for AADL ConclusionConclusion