Model-Based Embedded Real- Time Software Development Dionisio de Niz and Raj Rajkumar Real-Time and Multimedia Sys Lab Carnegie Mellon University

Para-Functionals Timeliness Guarantee End-to-end response time Reliability Tolerate Faults Throughput Data elements per second

Embedded Systems Composition = Software Hardware Embedded System Process Thread Process Thread +

Embedded Software Different Para-Functional Properties = Software Hardware Embedded System Throughput ( trajectories / s ) Reliability Process Thread Process Thread + Process Thread Process Thread radar scan track radar scan track radar scan

Embedded Software Heterogeneous Platforms Process Thread Process Thread pthread_create() Process Thread Process CreateThread() Process Thread Process Thread Process Thread New Thread() TCP/IP SocketsCANBusFlexRay

DRE Model Requirements Composability –Encode para-functionals –Compose them into final system Correctness –Reflect consequences of design choices –Prevent incorrect choices Fidelity –Reflect implementation & deployment Enable Reuse

Time Weaver DARPA – MoBIES funded project Component-Based Modeling Framework & Tool Build run time through models –Timing model Encode component relationships in “couplers” Decompose relationships of different aspects into different dimensions Enable recursive composition in functional and para-functional aspects Enable reuse of functional and para- functional constructs

Inter-component relationships decomposition Deployment Synchronization (Virtual Synchrony) Data dependency

Coupler Inter-component relationships decomposition Data dependency Synchronization (Virtual Synchrony) Deployment Coupler manipulate port elements to construct relationship

Basic Mechanisms of Couplers Property Propagation –Relate properties of associated components, e.g. period Constraints –E.g. both component not on same processor Synchronization –Arbitrarily complex synchronization protocol among group of ports (e.g. mutex, virtual synchrony, barrier) Inter-component communication –Mechanism used, e.g. invocation, CORBA, multicast –Specified at highest level (when network defined) –Automatic discovery and change of components affected

Independent Dimensions Functional Semantic Separation Projections to other dimensions Fault-ToleranceDeployment

Inter-dimensional projections Functional Deployment Network Processor

Modeling Dimensions in Time Weaver Functional –Functional relationships Deployment –Hardware description & binding Timing –Timing relationships (periods, deadlines) Fault-Tolerance –Replication Concurrency –Threading, synchronization Modality –Modes & mode switching

Ongoing Collaborations DARPA MoBIES Avionics OEP – Boeing, LM Software Radio – SwRI Automotive OEP – Berkeley, Ford & GM

Avionics OEP Rational ® Rose UML TimeWiz ® Target XML …      Time Weaver

Avionics OEP Interface with multiple tools Standard XML interfaces –IIF, AIF, ACL, Configurator Large model for scalability testing

Software Radio OEP Time Weaver (DSP Processing) Matlab TimeWiz® Linux

Software Radio OEP Unifying modeling of simulation and final run-time Generate matlab code for simulation Generate C++ code for final runtime (on Linux)

Automotive OEP uCOS-II / ARM TimeWiz® Time Weaver

Automotive OEP Take the simulation model to final running code Small footprint of network of processors –uCOS-II / ARM7

Summary Model of para-functional properties of DREs –New Abstraction: “coupler” Separation of para-functional properties in independent dimensions Ongoing experiments with Avionics, Automotive and Software Radio OEPs