adapteva epiphany iii - rochester institute of...

Adapteva Epiphany III

Bryan T. Meyers

May 7, 2015

Bryan T. Meyers Adapteva Epiphany III May 7, 2015 1 / 24

Introduction

Problem

I Current CMP architectures suffer from:I Power InefficiencyI Dark SiliconI Bandwidth Contention

I Increasing need for ASPs to build efficient devices

I New paradigms show promise, but do not address general purposecompute

Solution

Develop a new CMP architecture that is designed for high efficiencycompute and low thermal output, with a high-speed network-on-chip.

Introduction

Problem

I Current CMP architectures suffer from:I Power InefficiencyI Dark SiliconI Bandwidth Contention

I Increasing need for ASPs to build efficient devices

I New paradigms show promise, but do not address general purposecompute

Solution

Develop a new CMP architecture that is designed for high efficiencycompute and low thermal output, with a high-speed network-on-chip.

Introduction

Adapteva

I Founded 2008 in Lexington, MassachusettsI Goal

I Build the most-efficient CMP in the worldI Lead the way to next-gen compute scales

I Used Kickstarter to raise $100 million to build the Parallella

Parallella

Platform

Figure: Adapteva Parallella

Specifications

I Xilinx ZynQ 7010-7020I 800 MHz Dual-core ARM A9I FPGA

I Adapteva Epiphany IIICoprocessor

I 1GB DDR2 SDRAM

I MicroSD Card

I Ethernet HDMI

I GPIO

Parallella

Architecture

Figure: Parallella High-Level Architecture

Introduction

Specifications

I 16-core CMPI Cores

I 32-bitI 1 GHz Superscalar RISCI 32KB Multibank SRAMI DMA

I 2D Mesh Network on Chip

I 2W TDP

Adapteva Epiphany III Architecture

Overview

Tilera?

Overview

Tilera?

Core - Memory

Networking

Limitations

I Slow Host toCoprocessor Link

I No Send/Receive

I Only 32-bit FP

I Interrupted by RemoteRead/Write

Memory

I Only 32KB per core

I No MemoryManagement

Network

I Reads are Requests toWrite

I Load/Store notSend/Receive

Limitations

I No Send/Receive

I Only 32-bit FP

Memory

Network

Limitations

I No Send/Receive

I Only 32-bit FP

Memory

Network

Limitations

I No Send/Receive

I Only 32-bit FP

Memory

Network

Programming

OpenCL

I Open-source OpenCLimplementation

I SupportsI X86I ARMI CUDAI Epiphany

I Can access networkeddevices (cluster)

Programming

Epiphany SDK

I Host Library (EHAL)I Platform

ManagementI Program ManagementI Data Movement

I Device Library (ELIB)I Platform InfoI Data MovementI Mutex / Semaphore

Programming

Epiphany SDK

Programming

Epiphany SDK

Programming

Caveats

OpenCL

I DataI Assume Shared

Memory ArchitectureI Loads and StoresI Host to Coprocessor

Communication isSlow

I ComputationI Must have high

Computation toCommunication ratio

I Does not leveragelocal memorybandwidth

Epiphany SDK

I DataI No Memory

ManagementI Loads and StoresI Host to Coprocessor

I Steep Learning Curve

I May need Assembly torealize performance goals

Programming

Caveats

OpenCL

Epiphany SDK

I DataI No Memory

Programming

Caveats

OpenCL

Epiphany SDK

I DataI No Memory

Performance

Claims

I 2 Watt MaxTDP for 16 cores

I 32 GFLOPsI 1 FMAC /

cycle / coreI 1 GHz

I 512 GB/sOn-chip BW

I 8 GB/s Off-chipBW

Performance

Examination

Design

I Resembles a DSP closelyI Multi-bank memory to

allow faster accessI Memory Management

is ManualI Default heap

allocation is Off-chipI Must write linker file

to set up memoryspaces

Performance

I CalculationI Peak Performance Measured

by FMACI Integer MIPS = FP MIPSI Byte operations are 4 times

faster

I CommunicationI Major Bottleneck to HostI Reads are delayed WritesI Peak On-chip BW is for

Broadcast

Performance

Examination

Design

Performance

faster

Broadcast

Performance

Examination

Design

Performance

faster

Broadcast

Performance

Possible Improvements

Network

I Sends and ReceivesI Native MPI

I ScatterI GatherI BroadcastI Reduce

I Faster Link to Host

I Memory ManagementI Bank AllocationI Malloc/Free

I True Byte Addressing

I Larger Local Memory(64KB+)

I Caching(?)

Performance

Possible Improvements

Network

I Sends and ReceivesI Native MPI

I ScatterI GatherI BroadcastI Reduce

I Faster Link to Host

I Memory ManagementI Bank AllocationI Malloc/Free

I True Byte Addressing

I Larger Local Memory(64KB+)

I Caching(?)

Performance

References

I Adapteva.com

I Parallella

I Epiphany III Datasheet

I Epiphany Architecture Reference

I Parallella Manual

Questions?

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