1. ITEA Dependable Component Based Software for CE Devices Robocop & Space4U Experiences Tutorial at ICCE 2006

2. ITEA Robocop & Space4U TutorialICCE – 2006page 2 of ??? Outline Introduction Architecture Component Model Resource Management Fault Management Real-Time Prediction Wrap-Up Robocop Component Resource Model Simulation Model … … Functional Model Executable Component Component Model Analysis & Integration Trading & Deployment Trading & Deployment Resource Management Download Terminal Management Fault Management Service logic other Middleman logic other Middleman logic

3. ITEA Robocop & Space4U TutorialICCE – 2006page 3 of ??? Performance Prediction Framework joint work with M.R.V.Chaudron Objectives: At the design phase –Graphically compose an assembly from components –Predict performance properties of an assembly Task latencies Number of missed deadlines Processor, bus, memory load –Note: without even buying the constituent components!

4. ITEA Robocop & Space4U TutorialICCE – 2006page 4 of ??? Real-time Property Prediction Abstract example: CompC CompB CompACompD StimulusResponse Is Response Time within TMin and TMax? Video decoder example: VLD Inverse Quantizer Inverse DCT …011010101… bit-stream of a frame reconstructed frame Decoder Decoding task latency < 40 ms

5. ITEA Robocop & Space4U TutorialICCE – 2006page 5 of ??? Application Domains Hard real-time systems –Task lateness leads to catastrophic results anti-lock braking system air-bag controller Firm real-time systems –No catastrophic consequences, but value of the function = 0 car navigation surveillance camera Soft real-time systems –Task lateness reduces a value of the function multimedia, video and audio codecs electronic game

6. ITEA Robocop & Space4U TutorialICCE – 2006page 6 of ??? Case Study: MPEG Decoder Requirements –MPEG4 decoder functionality –Rate of skipped frames <= 1% Refreshment frequency is 25 frames/sec Missing deadline for decoding task <= once per 4 sec Given –Remote repository with various components and services Reader FIFO Buffer Reader MPEG4 Decoder Reader Renderer Goal: without even buying the components –Assess the performance and timeliness of a designed assembly

7. ITEA Robocop & Space4U TutorialICCE – 2006page 7 of ??? Performance Prediction Approach (1/2) The approach is a four-step strategy: The component developer specifies –behaviour model of a component –resource model of a component Application developer: –composes selected components/services and –selects scenario of interest & models this scenario (application scenario model) These three models are compiled together –into a model of the execution architecture (incl. concurrent tasks) For each scenario the tasks execution is simulated –  execution timeline of tasks

8. ITEA Robocop & Space4U TutorialICCE – 2006page 8 of ??? Performance Prediction Approach (2/2) Input Application requirements Design (assemble) Real-time application Models Component Resource model Component Resource model Component Behaviour model Component Behaviour model has Compile models / reconstruct tasks Execution architecture (tasks) Simulate task execution Task execution timeline Validate Real-time and performance properties Analyze predicted for Construct Application Scenario model Application Scenario model ! ! ! Real-time aware components Real-time aware components Select

9. ITEA Robocop & Space4U TutorialICCE – 2006page 9 of ??? Characteristics of Models Reflect the implementation at higher abstraction level Behaviour model –for each operation specifies a sequence of invocations of operations of other interfaces Resource model –contains processing, bandwidth and memory usage of each component operation Application Scenario model: –assembly structure, specific for this scenario –environmental events or system interrupts (task triggers) Resource, Behaviour and Scenario models are composable –composed model represents an execution architecture (task pool) of a whole application

10. ITEA Robocop & Space4U TutorialICCE – 2006page 10 of ??? Behaviour and Resource Models BehavourModel_MPEG4Decoder_Component behaviour operation IDecode.decodeFrame() calls IBufferAccess.getElement() passedBits = 0 returnedBits = 1024 synchronous = TRUE numberOfIterations = 1 calls IBufferAccess.storeElement() passedBits = 1024 returnedBits = 1 synchronous = TRUE numberOfIterations = 1 BehavourModel_MPEG4Decoder_Component behaviour operation IDecode.decodeFrame() calls IBufferAccess.getElement() passedBits = 0 returnedBits = 1024 synchronous = TRUE numberOfIterations = 1 calls IBufferAccess.storeElement() passedBits = 1024 returnedBits = 1 synchronous = TRUE numberOfIterations = 1 ResourceModel_MPEG4Decoder_Component resource use operation IDecode.decodeFrame() cpu claim max = 1E7 cycles (reference processor) aver = 1E5 cycles (reference processor) min = 1E4 cycles (reference processor) mem claim = 10 KB mem release = 3 KB ResourceModel_MPEG4Decoder_Component resource use operation IDecode.decodeFrame() cpu claim max = 1E7 cycles (reference processor) aver = 1E5 cycles (reference processor) min = 1E4 cycles (reference processor) mem claim = 10 KB mem release = 3 KB IDecodeIBufferAccess decodeFrame() getElement() storeElement()

11. ITEA Robocop & Space4U TutorialICCE – 2006page 11 of ??? Composing MPEG4 Decoder Assembly Out of selected services vReader: Reader IRead rBuffer: FIFO Buffer IBufferAccess vDecoder: MPEG4Decoder IDecode IBufferAccess wBuffer: FIFO Buffer IBufferAccess vRenderer: Renderer IWrite IBufferAccess

12. ITEA Robocop & Space4U TutorialICCE – 2006page 12 of ??? Processing Node: MIPS 130 Specifying Scenario Model vReader: Reader IRead rBuffer: FIFO Buffer IBufferAccess vDecoder: MPEG4Decoder IDecode IBufferAccess wBuffer: FIFO Buffer IBufferAccess vRenderer: Renderer IWrite IBufferAccess Task Trigger – can be implemented in glue code as a POSIX thread with periodic events Invokes IWrite.renderFrame() every 40 ms Invokes IDecode.decodeFrame() every 40 ms Invokes IRead.readFrame() every 40 ms

13. ITEA Robocop & Space4U TutorialICCE – 2006page 13 of ??? Composing the Models (1/3) Input Application requirements Design (assemble) Real-time application Models Component Resource model Component Resource model Component Behaviour model Component Behaviour model has Compile models / reconstruct tasks Pool of tasks in application Simulate task execution Task execution timeline Validate Real-time and performance properties Analyze predicted for Construct Application Scenario model Application Scenario model

14. ITEA Robocop & Space4U TutorialICCE – 2006page 14 of ??? The generated task specifies sequence of constituent method invocations period, deadline, priority, synchronization constraints Composing the Models (2/3) Service_A Service_B Operation_B Operation_C Service_CService_D Operation_D Operation_F Service_F Operation_E Task Trigger (period 40 ms) Operation_A TaskTrigger invoke InterfaceX.OperationA period 40 ms offset 0 ms deadline 40 ms Application Scenario Model: Component Resource Model: Operation_E CPU claim = 3ms 30 ms Component Behavior Model: OperationA() calls InterfaceZ.OperationB() InterfaceY.OperationC() nmbIterations = 1

15. ITEA Robocop & Space4U TutorialICCE – 2006page 15 of ??? Composing the Models (3/3) vReader: Reader IRead rBuffer: FIFO Buffer IBufferAccess vDecoder: MPEG4Decoder IDecode IBufferAccess wBuffer: FIFO Buffer IBufferAccess vRenderer: Renderer IWrite IBufferAccess Task Trigger Invokes IWrite.renderFrame() every 40 ms Invokes IDecode.decodeFrame() every 40 ms Invokes IRead.readFrame() every 40 ms

16. ITEA Robocop & Space4U TutorialICCE – 2006page 16 of ??? Simulation and Analysis (1/2) Input Application requirements Design (assemble) Real-time application Models Component Resource model Component Resource model Component Behaviour model Component Behaviour model has Compile models / reconstruct tasks Pool of tasks in application Simulate task execution Task execution timeline Validate Real-time and performance properties Analyze predicted for Construct Application Scenario model Application Scenario model

17. ITEA Robocop & Space4U TutorialICCE – 2006page 17 of ??? Simulation and Analysis (2/2) Simulation time Mem load Simulation time Bus load Simulation or Schedulability analysis are performed with scheduling algorithms deployed on the target OS (RMA, EDF, CBS) Simulation results in task latencies, number of missed deadlines, CPU, memory and bus utilization

18. ITEA Robocop & Space4U TutorialICCE – 2006page 18 of ??? Validation against Requirements Video Decoding Task: Related REQ: “Skipped frames rate < 1% ” Decision on acceptance of the composed assembly –If “not accept”: try different component configurations, or other components –If “accept”: buy the components, implement application-level glue code, test and deploy

19. ITEA Robocop & Space4U TutorialICCE – 2006page 19 of ??? Not mentioned Facilities and Benefits Modelling of parameter-dependent behaviour and resource usage Multiple-platform resource models Task synchronization aspects can be modeled Component mapping on multiprocessor architecture Multidimensional design space exploration –robusteness vs cost, memory_load vs cpu_load, etc

20. ITEA Robocop & Space4U TutorialICCE – 2006page 20 of ??? Framework Deployment Issues We have developed a tool chain supporting the design activities We have validated the prediction approach by MPEG4 Decoder case study: –prediction accuracy of general performance is > 90% –prediction accuracy on task latencies is > 70% Real-Time Prediction Framework

21. ITEA Robocop & Space4U TutorialICCE – 2006page 21 of ??? RTIE Graphical Composer