apecs: an aadl and polychrony based embedded computing...

Problem and MotivationApproach

Current Project StatusRelated Work

Conclusion

APECS: An AADL and Polychrony basedEmbedded Computing System Design

Environment with an Elevator Control Case Study

Matthew Anderson and Sandeep K. ShuklaVirginia Tech.

Partially funded by US Air Force Research Labs

Matthew Anderson and Sandeep K. Shukla Virginia Tech.AADL and Polychrony based Embedded Computing System Design Environment 1/ 24



Conclusion

Outline of the talk

1 Problem and Motivation

2 Approach

3 Current Project Status

4 Related Work

5 Conclusion




Conclusion

Platform DesignSoftwarePolychrony

Presentation Outline


2 Approach


4 Related Work

5 Conclusion




Conclusion


Platform Design

Architecture Analysis and Design Language (AADL)SAE International standard and framework for model basedsoftware systems

AADL and its accompanying tool suites provide a modelingenvironment that allow for modeling:

Target hardware platformsComplete software hierarchiesStatic and Dynamic system properties

Real-Time SchedulabilityResource Utilization




Conclusion


Software Hierarchy

OcarinaAn AADL tool suite developed in Ada to support buildingDistributed Real-Time Embedded Systems

Syntactic and Semantic AnalysisAutomated Code GenerationSupports a variety of software languages

C/C++AdaLustre and Esterel

So, what’s missing?




Conclusion


Motivations for Polychrony

A lack of formal semantics in C/Ada make verification difficult

Lustre and Esterel have fully synchronous specifications.Software specifications still require a fine granularity, at thethread or function level.Thread synchronization

OversynchronizationDeadlock

What can be done?→ Extend the backend of Ocarina with support for polychronousspecifications from MRICDF sources.




Conclusion



A lack of formal semantics in C/Ada make verification difficultLustre and Esterel have fully synchronous specifications.

Software specifications still require a fine granularity, at thethread or function level.Thread synchronization






Conclusion



A lack of formal semantics in C/Ada make verification difficultLustre and Esterel have fully synchronous specifications.Software specifications still require a fine granularity, at thethread or function level.

Thread synchronizationOversynchronizationDeadlock





Conclusion



A lack of formal semantics in C/Ada make verification difficultLustre and Esterel have fully synchronous specifications.Software specifications still require a fine granularity, at thethread or function level.Thread synchronization






Conclusion

Modeling the PlatformSoftware Development



2 Approach


4 Related Work

5 Conclusion




Conclusion


Elevator Design Study

APECS Design ApproachTop-down system model design illustrated using an ElevatorCase Study

Physical RequirementsCentralized ControlBank of four elevatorsService five floors

Safety and BehaviorTimely OperationSafe door operationFire emergency response




Conclusion


Top-Level Systems




Conclusion


Refining Systems




Conclusion


Refining Systems Cont’d




Conclusion


Door Behavior

State Table

State Machine




Conclusion


MRICDF Door Control Process




Conclusion


Clock Tree




Conclusion


MRICDF Door Control Process




Conclusion


Associating Software Behavior with AADL

process controllerFeatures

......

end controller

process implementation controller.cProperties

...source_name => "MRICDF_Controller";source_language => MRICDF;source_location => "../PATH";

end controller.c




Conclusion


Ocarina Generation Frontend

Frontend (AADL v 1.0 & v 2.0)

Parse AADL filesSyntactic AnalysisSemantic Analysis




Conclusion


Ocarina Generation Backend

Backend (Source Language)

ExpansionIntermediate TreeCode Generation




Conclusion


Dynamically Adding Threads




Conclusion


Dynamically Adding Threads Cont’d




Conclusion

Platform Design



2 Approach


4 Related Work

5 Conclusion




Conclusion

Platform Design

Status and Future Work

An extension has been written for Ocarina to accept codegenerated by MRICDFA new code generation option has been added for dynamicallyparsing and adding threads.

Planned Additions:Updates to MRICDF to streamline code generationInclusion of analysis for Real-time properties and codeverificationGenerate bus interface for distributed communication




Conclusion

Platform Design

Status and Future Work

An extension has been written for Ocarina to accept codegenerated by MRICDFA new code generation option has been added for dynamicallyparsing and adding threads.Planned Additions:

Updates to MRICDF to streamline code generationInclusion of analysis for Real-time properties and codeverificationGenerate bus interface for distributed communication




Conclusion

General ToolsOther Polychronous Developments



2 Approach


4 Related Work

5 Conclusion




Conclusion


Related AADL tools

A lot of work has been done on creating tools for AADLdevelopment:

OSATE as an environment for textual and graphicaldevelopementOcarina supports code generation from modelsCheddar performs software schedulability analysisA number of model verification and analysis tools: COMPASSand BIP




Conclusion


AADL to Signal

”Toward polychronous analysis and validation for timed softwarearchitectures in AADL”Y. Ma, H. Yu, T. Gautier, P. Le Guernic, J.P. Talpin, L.Besnard, and M. Heitz

Translates an entire AADL model into SignalFormally analyze the translated modelSimulate the behavior of the translated model

Instead APECS:Acts as an extension of the AADL development environmentIs aimed at generating executables for the targeted physicalplatform




Conclusion



2 Approach


4 Related Work

5 Conclusion




Conclusion

Conclusion

The APECS framework is based on the AADL developmenttools Osate / Ocarina and the polychronous tool EmCodeSynAPECS provides a environment for modeling end to endsystemsSoftware behavior is explicitly specified and formally verifiable

As opposed to informal specifications in C or AdaFree from additional synchronization constrainsts ofEsterel/Lustre

We illustrate this with the Elevator System


Any Questions?

apecs: an aadl and polychrony based embedded computing...

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