a flexible simulator for control- dominated distributed real-time systems johannes petersson...

A flexible simulator for control-A flexible simulator for control-dominated distributed real-time dominated distributed real-time

systemssystems

A flexible simulator for control-A flexible simulator for control-dominated distributed real-time dominated distributed real-time

systemssystems

Johannes PeterssonIDA/SaS/ESLAB

Johannes PeterssonIDA/SaS/ESLAB

Master’s Thesis presentationMaster’s Thesis presentation

ExaminerPetru ElesExaminerPetru Eles

SupervisorPaul PopSupervisorPaul Pop

22Johannes Petersson, IDA/SaS/ESLABJohannes Petersson, IDA/SaS/ESLAB Master’s Thesis presentation 2003.04.10Master’s Thesis presentation 2003.04.10

OutlineOutline

Introduction Control-dominated systems Modelling Embedded system design Simulation A simulator for control-dominated systems Experimental results Conclusion and future work

Introduction Control-dominated systems Modelling Embedded system design Simulation A simulator for control-dominated systems Experimental results Conclusion and future work


IntroductionIntroduction

Embedded systems

Motivation Test for correctness Validate timing behaviour Cost, size and power reduction

Embedded systems

Motivation Test for correctness Validate timing behaviour Cost, size and power reduction


Control-dominated systemsControl-dominated systems

Embedded systemsEmbedded systems

Real-time systemsHomogeneous or heterogeneous

Real-time systemsHomogeneous or heterogeneous

Distributed R-T SystemsDistributed R-T Systems




System overview System overview Control function Control function

Modes

Controller

Physicalenvironment

User

Actuators Sensors

Switches Instruments

Desired outputDesired output Actual outputActual output

Leads to the need of iterative design stepsLeads to the need of iterative design steps


ModellingModelling

System model System model

CA

N

TT

PCAN C

AN

TTP CA

N

TTPTasks Tasks

Tasks

Tas

ksT

asks

Distributed Heterogeneous Mapped WCET Scheduled

Distributed Heterogeneous Mapped WCET Scheduled


ModellingModelling

Application model Application model

Conditional Process Graph• Processes

• Conditions

• Mapping

• Resources

• Sensors

• Actuators

• Functionality

Conditional Process Graph• Processes

• Conditions

• Mapping

• Resources

• Sensors

• Actuators

• Functionality

P0

Sensor

Actuator

P1

P3P2

P4

Resource 1

Resource 2

while (0!=1) { ...}

A -A


P4P4 P5P5

P7P7

P13P13

P15P15

First processor Second processor ASIC

CC

DD

P0

P18

P1P1

P2P2 P3P3

P6P6

P8P8 P9P9

P10P10

P11P11

P12P12

P14P14 P16P16

P17P17

C

KK

P0

P18

P1

P2 P3

P6

P8 P9

P10

P11

P12

P14 P16

P17

Subgraph corresponding to DCK

Conditional Process GraphConditional Process Graph


Embedded system designEmbedded system design

Design flow Design transformations

Functional partitioning Allocation and mapping

Scheduling

Design flow Design transformations

Functional partitioning Allocation and mapping

Scheduling


Design flowDesign flow

Design steps Design steps

Systemspecification

Architectureselection

Partitioning

Scheduling

Hardwaresynthesis

Softwaresynthesis

Integration

Simulation


Design transformationsDesign transformations

Functional partitioning Functional partitioning

Split processes Split processes

Merge processes Merge processes


Design transformationsDesign transformations

Allocation and mapping Allocation and mapping

Allocating resources Mapping processes

Allocating resources Mapping processes

Resource

Resource

Resource

Tasks

P1

P2 P3

P4


Design tasksDesign tasks

Scheduling Scheduling

Tasks

Resources

Schedule table

Decide on a scheduling algorithm and perform the scheduling

Pre-emptive / non pre-emptive

Dynamic / static

Decide on a scheduling algorithm and perform the scheduling

Pre-emptive / non pre-emptive

Dynamic / static


Simulation introductionSimulation introduction

Discrete- and continuous-time Discrete- and continuous-time

ActuatorsSensors

Tasks

Discrete-time

Continuous-time Vehicle

Evaluate-update Discrete events Evaluate phase Update phase

Evaluate-update Discrete events Evaluate phase Update phase

ActuatorP1 P2Senso

rP1 P2 ActuatorSensor


Related workRelated work

Simulators reviewed True Time The Network Simulator SystemC’s simulator engine Etc.

Extended Task Graphs (eTG) Process graph with conditional constructs eTG to SystemC translator

• Stephan Klaus, Automatic generation of scheduled SystemC models

• Doesn’t consider the conditional constructs• Inspirational source

Simulators reviewed True Time The Network Simulator SystemC’s simulator engine Etc.

Extended Task Graphs (eTG) Process graph with conditional constructs eTG to SystemC translator

• Stephan Klaus, Automatic generation of scheduled SystemC models

• Doesn’t consider the conditional constructs• Inspirational source


SystemCSystemC

Basics Basics

Provides an evaluate-update simulation engine Possible to implement any scheduling policy Models both hardware and software Work at different abstraction levels

Provides an evaluate-update simulation engine Possible to implement any scheduling policy Models both hardware and software Work at different abstraction levels

A C/C++ library A C/C++ library

A de facto open source standard A modelling platform and language for system-

level co-design Spans from concept to implementation

A de facto open source standard A modelling platform and language for system-

level co-design Spans from concept to implementation


Module 1 Module 2

SystemC ConceptsSystemC Concepts

Hierarchical modules Hierarchical modules May contain processes and other modules

• SC_MODULE

May contain processes and other modules• SC_MODULE

Communication Communication The modules and processes communicate

through signals passed through ports The modules and processes communicate

through signals passed through ports

Three types of processes Three types of processes Asynchronous-function (SC_METHOD)

Asynchronous-thread (SC_THREAD)

Synchronous-thread (SC_CTHREAD)

Asynchronous-function (SC_METHOD)

Asynchronous-thread (SC_THREAD)

Synchronous-thread (SC_CTHREAD)


A simulator for control-dominated systemsA simulator for control-dominated systems

Overview Overview

Schedulingprogram

P0

Sensor

Actuator

P1

P3P2

P4

Resource 1

Resource 2

while (0!=1) { ...}

graph.xml

tasks.xmlallocation.xml graph.xml

allocation.xml

schedule.xml

schedule.xml

cpg2scThe SystemC

generator

ExecutableSystemC

code



Representation Representation

P0

Sensor

Actuator

P1

P3P2

P4

Resource 1

Resource 2

while (0!=1) { ...}

Tasks.xml<task>

<name>Task_01</name>

<wcet>5</wcet>

<condition>Cond_A</condition>

<sensor>Sensor_01</sensor>

<actuator>null</actuator>

<code>

<![CDATA[ while (0!=1) { ... } ]]>

</code>

</task>

Tasks.xml<task>


<wcet>5</wcet>

<condition>Cond_A</condition>

<sensor>Sensor_01</sensor>

<actuator>null</actuator>

<code>

<![CDATA[ while (0!=1) { ... } ]]>

</code>

</task>

Graph.xml<task>


<wcet>5</wcet>

</task>

<edge>

<name>Arc_01</name>

<wcet>1</wcet>

<connects>

<from>Task_01</from>

<to>Task_02</to>

</connects>

</edge>

Graph.xml<task>


<wcet>5</wcet>

</task>

<edge>

<name>Arc_01</name>

<wcet>1</wcet>

<connects>

<from>Task_01</from>

<to>Task_02</to>

</connects>

</edge>graph.xml

tasks.xmlallocation.xml

Allocation.xml<processor>

<name>PR2</name>

<tasks>

<task>Task_01</task>

</tasks>

</processor>

<bus>

<name>B1</name>

<edges>

<edge>Arc_01</edge>

</edges>

</bus>

Allocation.xml<processor>

<name>PR2</name>

<tasks>


</tasks>

</processor>

<bus>

<name>B1</name>

<edges>

<edge>Arc_01</edge>

</edges>

</bus>



Scheduling Scheduling

Schedulingprogram

graph.xml

allocation.xml

schedule.xml

Schedule.xml<column>

<start_time unit=”ms”>10

</start_time>

<conditions>

<cond>!Cond_A</cond>

<cond>Cond_B</cond>

<tasks>


</tasks>

</conditions>

</column>

Schedule.xml<column>

<start_time unit=”ms”>10

</start_time>

<conditions>

<cond>!Cond_A</cond>

<cond>Cond_B</cond>

<tasks>


</tasks>

</conditions>

</column>

process True C C & D C & -D

P1 0

P2 5

P4 14 14

P5 45 45

P6 51 50

P7 3



cpg2sc cpg2sc

graph.xml

tasks.xmlallocation.xml

schedule.xml

cpg2scThe SystemC

generator

ExecutableSystemC

code

Tasks Stored in one SC_Module

• Consist of several SC_Thread

Controller Stored in one SC_Module

• Consist of one SC_Thread

Main program One SC_Main function

• Binds all ports to signals

• Starts the simulation

Tasks Stored in one SC_Module

• Consist of several SC_Thread

Controller Stored in one SC_Module

• Consist of one SC_Thread

Main program One SC_Main function

• Binds all ports to signals

• Starts the simulation


ImplementationImplementation

A day at work.

A day at work.


Simulation resultsSimulation results

Basic setup: Part of a Cruise Controller Basic setup: Part of a Cruise Controller

P1

P3

P7

P11

P13

P15

P2

P5

P9

P6

P14

P4

P0A A

P12

P10P8

Sensor

Actuator1 Actuator4

Actuator3

Actuator2

Resource 1 Resource 2



Functional partitioning Functional partitioning

P1

P3

P7

P11

P13

P15

P2

P5

P9

P6

P14

P4

P0A A

P12

P10P8

Sensor

Actuator1 Actuator4

Actuator3

Actuator2


P1

P7

P9

P2

P8

P0A A

Sensor

Actuator1 Actuator4

Actuator3

Actuator2


P4

P3 P5

P6

Throttle angleThrottle angle Fuel injectionFuel injection



Conditions and resource allocation Conditions and resource allocation

P1

P3

P7

P11

P13

P15

P2

P5

P9

P6

P14

P4

P0

P12

P10P8

Sensor

Actuator1 Actuator4

Actuator3

Actuator2


P1

P3

P7

P11

P13

P15

P2

P5

P9

P6

P14

P4

P0A A

P12

P10P8

Sensor

Actuator1 Actuator4

Actuator3

Actuator2

Resource 1

P1

P3

P7

P11

P13

P15

P2

P5

P9

P6

P14

P4

P0

P12

P10P8

Sensor

Actuator1 Actuator4

Actuator3

Actuator2

Resource 1

Fuel injectionFuel injection



Mapping Mapping

P1

P3

P7

P11

P13

P15

P2

P5

P9

P6

P14

P4

P0A A

P12

P10P8

Sensor

Actuator1 Actuator4

Actuator3

Actuator2

Resource 1

P1

P3

P7

P11

P13

P15

P2

P5

P9

P6

P14

P4

P0

P12

P10P8

Sensor

Actuator1 Actuator4

Actuator3

Actuator2


P1

P3

P7

P11

P13

P15

P2

P5

P9

P6

P14

P4

P0A A

P12

P10P8

Sensor

Actuator1 Actuator4

Actuator3

Actuator2



Fuel injectionFuel injection


Simulation resultsSimulation results Waveform diagram Waveform diagram


Conclusion and future workConclusion and future work

Conclusion Implemented a simulator for control

dominated distributed real-time systems SystemC used as the simulator’s engine Successfully used in evaluating several design

transformations Future work

Add more scheduling policies• Fixed-priority pre-emptive scheduling

Refine communication• TTP, CAN, etc.

Conclusion Implemented a simulator for control

dominated distributed real-time systems SystemC used as the simulator’s engine Successfully used in evaluating several design

transformations Future work

Add more scheduling policies• Fixed-priority pre-emptive scheduling

Refine communication• TTP, CAN, etc.


Thank youThank you

Thanks to everybody for listening

Thanks to Petru Eles and Paul Pop

Thanks to everybody for listening

Thanks to Petru Eles and Paul Pop

a flexible simulator for control- dominated distributed real-time systems johannes petersson...

Documents

design flowdesign steps

design tasksschedulingdecide

need of iterative design

conditional constructsetg

flexible simulator

systemlevel codesignspans

scheduling policymodels

scheduling algorithm