milan: technical overview october 2, 2002 akos ledeczi [email protected] milan workshop...

MILAN:

Technical Overview

MILAN:

Technical Overview

October 2, 2002

Akos [email protected]

http://milan.usc.edu/

MILAN Workshop

Institute for Software Integrated Systems

Vanderbilt University

Copyright © 2002 Vanderbilt University 2MILAN Workshop, Nashville, October, 2002

Outline

• Brief overview

• Modeling methodology

• Integrated simulators/tools

• Design flow with MILAN

• The kind of feedback we’d like to get


MILAN Objectives

MILAN is a model-based, extensible simulation framework.

It will provide a unified environment capable of:– modeling a large class of embedded systems and

applications– seamlessly integrating different widely-used simulators

into a single framework– enabling rapid evaluation of different performance

metrics such as power, latency, and throughput– facilitating simulation at multiple levels of granularity– rapid evaluation of a large design space


HOW?Model Integrated Computing

• Configurable modeling, analysis and program synthesis environment

• Rich, domain-specific modeling language• Primarily graphical, hierarchical, multiple-aspect

models• Open, extensible tool environment with standard

interfaces (XML, COM, UML, OCL)• Mature toolset in everyday use in industry

(GM, Sandia, Boeing, NASA, etc.)

Generic Modeling Environment (GME 2000)


The MILAN Architecture

Model interpreterfeeding-back results

Model interpreterdriving simulators/tools

System Generation and Synthesis Tools

GME 2000

Resource Models

Application Models

Constraints

MappingModels

iiTarget System

i

Functional Simulators

High-levelPerformance Estimators

Cycle-Accurate

Performance Simulators

Design SpaceExploration

Tools

Functional Simulators

High-levelPower

Estimators

Cycle-Accurate

Power Simulators

Design SpaceExploration

Tools

ii

i • DESERT

• Matlab• SystemC• ActiveHDL

• HiPerE

• SimpleScalar• PowerAnalyzer• Armulator• CodeComposer

MILAN v0.9


(Much) Simplified Operation

CodeGenerator

DataflowKernel

App-SpecificLibraries





DSPLibraries

GlueCode

Compiler/Linker

Exe

Dataflow Graph

Application Code

MILAN Modeling

MILAN Model Interpretation

Not shown:• Design space modeling and exploration• Requirement modeling• Resource modeling• Support for several simulators• Support for configurable hardware• Multi-granular simulation support• Auto-feedback from simulators• etc.


Application Models

• Dataflow• Mixed synchronous and

asynchronous• Strongly typed• Supports parametric

models• Explicit alternatives• Supports components

with functionality implemented in hardware (targets SystemC and VHDL)

• Modeling support for multi-granular simulation


Resource Models

• Supports a large class of building-blocks (computing cores, memories, interconnects, etc.)

• Resources can be modeled at varying granularities

• Single modeling paradigm for several heterogeneous architectures

• The parameters captured by the model represent:– Capabilities and flexibilities

provided by the architecture– Options that can be exploited

for power and time optimization– Input needed by the integrated

simulators


Other Models

• Constraints:– Capture requirements (performance, power, cost, etc.),

resource constraints, etc.– OCL-based representation– Act as “knobs”:

• can be placed anywhere in the hierarchy• can be easily adjusted for experimentation• drive design space exploration

• Mapping:– Application models contain references to one or more hw

resources (or relation)– Contain performance, power, etc. attributes


XMLDesignSpaceRep.

Design Space Exploration

App Space

Constraints

Binary Encoding

OBDD Representation

OBDD Representation

Symbolic Design Space

Pruned Design Space

SymbolicConstraint

Satisfaction

Re-encoding/Iterative Pruning

Symbolic Design Space Representation

Parsing/ Composing

Symbolic Constraint Representation

HW SpaceBinary

EncodingOBDD

Representation

XML

I/F

XML

I/F

DEsign Space ExploRation ToolMILAN/GME

• Generic, domain-independent, constraint-based design space exploration tool, leveraging DARPA ACS technology

• Tool interfaces specified and synthesized from meta-models, leveraging DARPA MoBIES technology for facilitating tool integration

• Extensions planned to enable representation of alternatives in the resource space• Results will be leveraged by DARPA PCA and MoBIES programs

i


High-level Performance Estimator

• Objectives– Integrate component specific models

– rapid system-wide power and performance evaluation

– based on parallelism, operation-states, data transfer cost

– estimated value within an error range of ±10%

• Input/Output

High LevelPerformance

Estimator

OUTPUT

PowerConsumption

Execution Time

Operation StatesTrace

<system level>INPUT

<component level>

Mapping

Schedule

Component SpecificPerformance Values

Architecture DescriptionModel Information


Design Space Exploration

10k

k = 1..3

Design Space

1

Design Space

n >> 1

10n

Design SpaceResource

Application

Co

ns

train

ts

Co

ns

tra

ints

DESERT

Human-in-the-loop feedback

HiPerEIterator


Simulators

• Functional: Matlab, SystemC and VHDL

• High-level: HiperE

• Cycle accurate: SimpleScalar, SimplePower, PowerAnalyzer, Armulator, Code Composer:– Use C code generated from app models– Use configuration files generated from resource models


Design Flow with MILAN

Resource

Application

Co

ns

train

tsC

on

str

ain

ts

DESERTLoopingHiPerE

MatlabSystemC

ActiveHDL

PowerAnalyzeSimpleScalar

Armulator

HiPerEHiPerE

System Generation and Synthesis Tools

Target System

Automated Process

Human-in-the-loop Process

Mixed Process


Feedback

• What additional processors, hardware architectures should MILAN support?

• What additional simulators should MILAN support?• What additional runtime kernels should MILAN

support?• Are there any other problems or issues you want to

raise?• Are there any other remarks or observations you

want to make?

milan: technical overview october 2, 2002 akos ledeczi [email protected] milan workshop...

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