esl: panacea or hype?

June 22, 2005 IRISATECH DAY

ESL: Panacea or Hype?

FERMAT | Sandeep Shukla | June 2005

{shukla}@vt.edu

Acknowledgement: NSF, Project Espresso @IRISA, FERMAT @Virginia Tech, and the “Chip Design” Magazine


Outline• Pictures speak louder than words

− What is ESL?− Abstraction Trends− Verification Trends− EDA Industry Trends

• What are we doing?− Heterogeneity and MoCs− Behavioral Hierarchy− Meta Modeling Support− Service Oriented Validation Framework


Hardware Resources and Computer Power


HW/SW Cost Breakdown Trends


Abstraction Trends


Hybrid and AMS


Electronic System Level?


Verification Trends


Verification Gap


Verification Trends


A Tale of Two ESLs?


ESL Industry Space


Our Work at FERMAT and ESPRESSO• Introduce Heterogeneity in SystemC with Models

of Computation (MoC) extensions• Raise the Modeling Fidelity• Step towards Behavioral Hierarchy with

Heterogeneity• EWD: Meta-Modeling Frameworks• CARH: Service Oriented Validation Framework


SystemC’s Discrete-Event Kernel

• Evaluate-Update Paradigm

• Dynamic scheduling incurs unnecessary delta cycles

• Statically schedulable MoCs should avoid dynamic scheduling


An Example MoC Extension: Synchronous Data Flow in SystemC• SDF models are:

− Amenable to static scheduling− Require blocks to have predefined production and

consumption rates− Construct repetition vector− Construct firing order− Executable schedule achieved with valid repetition

vector and firing order


An Example MoC Extension: Synchronous Data Flow in SystemC• Constructing an SDF model requires:

− Encapsulating SDF specific processes (SC_SDF_METHOD) in a top-level SystemC process

− Top-level constructs SDF graph with appropriate API

− Every unique SDF model must be registered in its own sdf_graph instance

− Top-level entry function must invoke sdf_trigger() function

SC_MODULE( sdf_block )

{

SDFPort< sc_uint< 8 > > sample_in;

SDFPort< sc_uint< 8 > > sample_out;

SC_SDF_METHOD( block_entry );

SC_CTOR( sdf_block ) {

// Register this block into sdf_graph

}

void block_entry() {

// Entry specific code

}

};

SC_MODULE( toplevel ){

sc_in_clk CLK;SC_THREAD( topentry ) { sensitive << CLK.pos();};SC_CTOR ( toplevel ) { // Instantiate SDF blocks and connect // the ports}void topentry() { sdf_trigger();}

};


An Example MoC Extension: Synchronous Data Flow in SystemC• During initialization all executable schedules are

computed• DE kernel continues executes without intervention

until sdf_trigger() is invoked• SDF kernel takes over and executes the SDF-

specific blocks according to the computed schedule


Heterogeneous ExtensionsCommunicating Sequential Processes• Rendez-vous communication

Phil1Phil4

Phil3

Phil0

Phil2

Fork1

Fork0

Fork4

Fork3

Fork2

Footman


Heterogeneous ExtensionsFinite State Machine• Control machines

Phil1Phil4

Phil3

Phil0

Phil2

Fork1

Fork0

Fork4

Fork3

Fork2

Footmans0 s1 s2 s3 s4


Heterogeneous ExtensionsDE, FSM, SDF & CSP

Phil1Phil4

Phil3

Phil0

Phil2

Fork1

Fork0

Fork4

Fork3

Fork2

Footman

DE: Solves RSA Encryption Algorithm

Producer Consumer

SDF: Producer/Consumer

SDF: Sobel EdgeDetectionAlgorithm


Simulation EfficiencyA brief look• Pure SDF models ~ 65% gains• Pure FSM models ~ 10% degradation• Pure CSP models ~ 1% gains


Behavioral Hierarchy with Heterogeneity • Decompose design into small behaviors• Behaviors expressed by different MoCs


Behavioral Hierarchy with Heterogeneity• Semantics define interactions within MoC and

across MoCs• Hierarchical composition


SystemCXML: http://systemcxml.sourceforge.net

SystemC Source

IR

Doxygen

Annotated XML

Phase 1

Extracted XML

Phase 2

Analysis, Transformation, Testing, Optimization, …

http://systemcxml.sourceforge.net/

http://systemcxml.sourceforge.net/


Service Oriented Validation• Service-oriented architecture

− Provide infrastructure for incorporating multiple features into services using ACE/TAO

− Use SCV for automated testbench generation− Dynamic-Value Change Dump− Logging Service

• Employ existing CORBA services such as:− Naming Service− Event Service


Meta-Modeling• Metamodeling frameworkMetamodeling framework

− Creating metamodelsCreating metamodels− Meta model allows an abstract descriptionMeta model allows an abstract description− Facilitates modeling using metamodel abstract Facilitates modeling using metamodel abstract − syntaxsyntax− Eg.: GME (Generic Modeling Environment)Eg.: GME (Generic Modeling Environment)

• GMEGME− Abstract syntax using pure UML class diagramsAbstract syntax using pure UML class diagrams− Semantic constraints using the Semantic constraints using the Object Constraint Object Constraint − Language (OCL)Language (OCL)− XML access for both model and metamodel XML access for both model and metamodel − informationinformation


Meta Modeling


Features of EWD

• A visual environment that supports heterogeneous modeling

• Executable simulation models are automatically built by the tool and currently the target simulation languages are

• SML and Haskell-based modeling extensions.

• Translation to other targets such as SMV for formal verification purposes

• Multi-targeting is achieved through XML-based interoperability


Reference

• Website for SystemC-H: http://fermat.ece.vt.edu/systemc-h/

• Book

http://fermat.ece.vt.edu/systemc-h/

esl: panacea or hype?

Documents

module sdf

ctor sdf

sdfspecific blocks

entry sc

method block

insdfport sc

synchronous data flow

orderan example moc