Network on Chip. 4 장. HW/SW Co-Design for SoC 2 Copyright ⓒ 2004 Levels of IC architecture

Network on Chip

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4 장 . HW/SW Co-Design for SoC

Levels of IC architecture

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4 장 . HW/SW Co-Design for SoC

Emerging Platforms & Architectures

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4 장 . HW/SW Co-Design for SoC

단일 반도체 칩 상에 통신망 구조를 이식단일 반도체 칩 상에 통신망 구조를 이식 OSI modelOSI model 에 의해서 전송 프로토콜을 정의에 의해서 전송 프로토콜을 정의 DSP/microprocessor/Memory DSP/microprocessor/Memory 등을 등을 H/W-S/W co-design 이용 단일 칩 이용 단일 칩

내에서 연결내에서 연결 코드 최적화 및 저전력 software IP 라이브러리 구축 모듈간 연결을 위한 버스 구조 구성 요소

Region: Region: 특수한 토폴로지특수한 토폴로지 // 네트워크 구조를 허용하는 영역네트워크 구조를 허용하는 영역 BackboneBackbone Wapper : Wapper : 전송되는 메시지를 적절한 형태로 변환전송되는 메시지를 적절한 형태로 변환 , , 복잡하다복잡하다

복잡하고 대형 시스템에 적합복잡하고 대형 시스템에 적합

NoC (network on chip)U.C. BerkeleyU.C. Berkeley

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Wires-Centric Design Exploits logic structure to reduce wire loads Enables use of advanced circuits

wire properties and crosstalk known early and well characterized

Gives a stable design key wire loads don’t change with small logic

changes

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Wires dominate - power, area, delay

Problem - Contemporary tools leave wires as an afterthought result is lack of structure, visibility, and control

Solution 1 - wires first design route key wires, then place gates

Solution 2 - route packets, not wires on-chip networks

global wires fixed before the design starts

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Wires-first design

Floorplan

LocalNetlists

Library

ShortW ire

Models

Place &Route

Structure

Layout

ExtractorR & CTim ing

AnalysisSlowPaths

ManualDesign

RTLStructured

RTL

Regions

W ire plan Key W iresP lacem ent

& Loads

Synthesis

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On-Chip Interconnection Networks

Replace dedicated global wiring with a shared network

Dedicated wiring C hip

Loca lLogic

R outer

N etworkW ires

Network

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Bus-versus-Network

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NoC Challenges:

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Physical Issues Challenges

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Most Wires are Idle Most of the Time Don’t dedicate wires to signals, share wires across

multiple signals Route packets not wires Organize global wiring as an on-chip interconnection

network allows the wiring resource to be shared keeping wires busy

most of the time allows a single global interconnect to be re-used on multiple

designs makes global wiring regular and highly optimized

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Dedicated wires vs. Network

Dedicated Wiring On-Chip NetworkSpaghetti wiring Ordered wiring

Variation makes it hard to modelcrosstalk, returns, length, R & C.

No variation, so easy to exactlymodel XT, returns, R and C.

Drivers sized for ‘wire model’ –99% too large, 1% too small

Driver sized exactly for wire

Hard to use advanced signaling Easy to use advanced signaling

Low duty factor High duty factor

No protocol overhead Small protocol overhead

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Ideas from Networking and VLSI

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Communication

Structural layers of NOC

Regions

Resources

Hardware units

Executables

Functions

Applications

Configuration

Product

Channels and protocols

Processors, memorires, configurable HW, logic

System control, product behaviour

Resource types, buses, IO

Region types, switches, network interfaces

RTOS, code, HW configurations

Resource management, diagnostics, applications

Execution control, functions

Network management, allocation, operation modes

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Physical 신호 전압 , 타이밍 , 버스 폭 , 신호

동기 Data link

오류 검출 정정 Arbitration of physical medium

Network IP protocol 데이터 라우트

Transport TCP 프로토콜 End –to-end connection

Physical

Data link

Network

Transport

System/Session

Application

Network protocol

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NOC Platform development

Scaling problem How big NOC is needed? What are the application area

requirements? Region definition problem

What kind of regions are needed? What kind of interfaces between regions? What are the capacity requirements for the regions?

Resource design problem What is needed inside resources? Internal computation type and

internal communication? Application mapping flow problem

What kind of languages, models and tools must be supported? How to validate and test the final products?

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NOC Application Development Mapping problem

How to partition applications for NOC resources? How to allocate functionality effectively? Is the performance adequate? Is the resource usage in balance?

Optimisation problem How to perform global optimisation of heterogenuous applications?

How to define right optimisation targets? How to utilise application/resource type specific tools?

Validation problem Are the contraints met? Are the communication bottlenecks or power

consumption hot spots? How to simulate 10000 GIPS system? How to test all applications?

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NoC-Based System Design -I

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NoC Based System Design -II

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NoC-Based System Design -III

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Summary of NoC Systems Design

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OSI 모델을 데이터 전송 프로토콜로 사용 칩에 집적된 네트워크 (Network on Chip) 패킷 데이터 전송 대형 시스템이 구성 요소 이종 구성 요소의 칩 레벨 집적에 유리하다 .

S S S

resource

S

resource

S S S

resource

S

resource

S

resource

S

resource

S

resource

S

resource

S S

resource

S

resource

switch

rni

M

P

cre

rniP c

M

rni

MD

c

rni

M

P

cre

rniP c

M

rniP c

M

rni rni

rnirni

rni

rnirnirni

rnirni

mux Selectionlogic

mux

Selectionlogic

mux

Selectionlogic

muxSele

ctio

nlo

gic

mux

Selecti

on

logic

queue

queue

queue

SWITCH

스위치 네트워크 : CLICHE

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Square Switch

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Regions

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Physical Layer

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Physical Layer Phenomenon

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Data Link Layer

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Advanced Bus Techniques*

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Network Layer

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SPIN NoC*

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Transport Layer

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Application Program Layer

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Application (Software) Layers

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NoC Operating System

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Performance

CostVariability

SystemQuality

Energyconsumptio

n

Implementation

Development

Modifiability

VolumeFlexibility

Complexity

Functionality

ModularityCohesionCoupling

Programmability

ConfigurabilityApplicability

StructuralFunctional

Control

Manufacturability

LifetimeUsability

EffortTimeRisk

MaterialsLicencingProduction

Capacity

ComputationStorageCommunication

Fault toleranceResult quality (accuracy)Responsiveness

ScalabilityEfficiencyUtilisation

NoC 의 figure of Merit

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R. Marculescu

NoC 설계 flow

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BACKBONE

PLATFORMS

SYSTEMS

Baseband platform

Database platform

Multimedia platform

High-perforrmance communication systems

High-capacity communication systems

Virtual reality games

Entertainment devices

Personal assistant

Data collectionsystems

Low Power communication systemsLow Power communication systems

NoC 기반의 응용 분야

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Layered Radio Architecture

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Stream-based design

Processing

Element 1Stream Packet Stream Packet Stream PacketProcessing

Element 2

InterpretPacket

ConfigurationPipeline

Re-Constr.

Packet

ProcessingPipeline

Bypass Pipeline

Processing Layer

Application Layer Software

I/O Layer

Configuration Layer

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NoC 의 저전력 문제어플리케이션 레이어 - DPM, 리소스 관리 , 전력 관리 API

트랜스포트 레이어 - QoS 보장 ( 지연 및 메시지 손실 최소 ) 을 위한 데이터 패킷 관리 문제 , 메시지를 통한 PSM

네트워크 레이어 packetized 데이터 전송시 스위칭 및 라우팅 문제

데이터 링크 레이어 패킷 데이터 에러 손실 감축 및 복구 문제

Physical 레이어 - DVS 에 따른 신뢰성 문제 , 온 칩 동기 문제

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Tile-based Architecture PlatformR. Marculescu

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Energy-Aware Mapping for Tile-based Architectures

Objective: minimize the total communication energy consumptionConstraint: meet the communication performance constraints (specified by designer)For a 4X4 tile architecture, 16! mappings

R. Marculescu

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OFDM + CDMA2000 통합 Baseband 프로세서에 적용

Baseband processing

RF

Conversion

to IF

and A/D

CDMA2000

S/W part(DSP)

OFDM

S/W part(DSP)

Interconnection

(NoC)

H/W part

(ASIC)

Modulator

Demodulator

Despreader

Searcher

Time Tracker

AFC

Channel estimator

Lock detector

RAKE combiner

Power control

Channel codec

Rate matching

Multiplexing

I/O controller Process controller Program memory

CDMA2000 HW/SW Co-design

I/Q DemodulatorFFT Mode

Guard Interval Symbol Timing-

RecoveryCarrier Recovery

Channel Estimator Equalizer,

FEC Noise Filter

FFT

OFDM

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NoC Examples [Adriahantenaina et al., 2003] Adriahantenaina, A., Charlery, H., Greiner, A., Mortiez, L., and Zeferino, C. A. (2003). SPIN: a scalable packet switched on-chip micronetwork. In Proceedings of the Design Automation and Test Conference - Designer's Forum, pages 70{79. [Alho and Nurmi, 2003] Alho, M. and Nurmi, J. (2003). Implementation of interface router IP for Proteo network-on-chip. In Proc. The 6th IEEE International Workshop on Design and Diagnostics of Electronics Circuits and Systems (DDECS'03), Poznan, Poland. [Goossens et al., 2003] Goossens, K., Dielissen, J., van Meerbergen, J., Poplavko, P., Radulescu, A., Rijpkema, E., Waterlander, E., , and Wielage, P. (2003). Guaranteeing the quality of services in networks on chip. In Jantsch, A. and Tenhunen, H., editors, Networks on Chip, chapter 4, pages 61{82. Kluwer Academic Publishers. [Karim et al., 2001] Karim, F., Nguyen, A., Dey, S., and Rao, R. (2001). On-chip communication architecture for OC-768 network processors. In Proceedings of the Design Automation Conference, pages 678{683. [Nilsson et al., 2003] Nilsson, E., Millberg, M., �Oberg, J., and Jantsch, A. (2003). Load distribution with the proximity congestion awareness in a network on chip. In Proceedings of the Design Automation and Test Europe (DATE), pages 1126{1127.

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Some more technologies John Stockton Ad-hoc wireless networking, networks of sensors

– Emerging Zigbee wireless standard– UC Berkeley’s Smart Dust Project– Dust-Inc. (UC Berkeley spin-off company)– IEEE 802.15.4 Radios

• Hybrid CMOS SOM (System on Module) Solutions:– MEMS structures fabricated on top of CMOS– Film Bulk Acoustic Resonators (FBARs) over CMOS– Chemical sensors over CMOS

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John Stockton’s viewStockLabs Venture Consulting • Software & Compilers will drive chip architecture

– Processor architecture matters less and less– Custom datapaths by compilers replace specialized instrs– 10’s of processors per chip, MIMD becomes a way of life– “Freedom from Choice” - enables SOC scalability

• Chip Industry evolves to three levels of granularity– FPGAs as we know them today, flexible but low performance– Coarse-Grained FPGAs, better perf, but lose some flexibility– Structured ASIC with embedded reprogramability

• Software industry finally “gets it” on reliability / quality– Gains some of the discipline (restrictions) of the IC industry– Trades CPU Cycles for more robust applications

www.stocklabs.com

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Some Companies to watchJohn Stockton

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참고문헌 The Codesign of Embedded Systems : A Unified Hardware/Software

Representation, Sanjaya Kumar, James H.Aylor, Barry W.Johnson, Wm. A. Wulf

Synthesis and simulation of digital systems containing interacting hardware and software components 29th dac

A model and methodology for hardware-software codesign CAP Laboratory Homepage (http://peace.snu.ac.kr/) Pai Chou, Ross Ortega, Gaetano Borriello, "Synthesis of the Hardwar

e/Software Interface in Microcontroller-Based Systems," Proceedings of the IEEE/ACM International Conference on Computer-Aided Design, Santa Clara, CA, November 1992. pp.488-495.