SLAAC/ACS API: A Status Report Virginia Tech Configurable Computing Lab SLAAC Retreat March 1999

The Virginia Tech SLAAC Team Dr. Peter AthanasDr. Peter Athanas Dr. Mark JonesDr. Mark Jones Heather HillHeather Hill Emad IbrahimEmad Ibrahim Zahi NakadZahi Nakad Kuan YaoKuan Yao Diron DriverDiron Driver Karen ChenKaren Chen Chris Twaddle Jonathan Scott Luke Scharf Lou Pochet John Shiflett Peng Sarah Airey Chris Laughlin

Problem Definition A single adaptive computing board is insufficient for many applicationsA single adaptive computing board is insufficient for many applications Difficult to move an application from a research laboratory to practical applicationDifficult to move an application from a research laboratory to practical application Need for application to move to new platforms as they become available without unreasonable effortNeed for application to move to new platforms as they become available without unreasonable effort

Solution Approach Define a platform independent API that allows for configuration and control of a multi-board ACSDefine a platform independent API that allows for configuration and control of a multi-board ACS Provide efficient implementations of the API for research & field platformsProvide efficient implementations of the API for research & field platforms –exploit high speed networking –modular design that performs more complex control tasks on a OS-equipped host

Representative Field System Embedded, distributed systemEmbedded, distributed system –sensor nodes –actuator nodes –adaptive computing nodes Limited OS/ microprocessor support on most nodesLimited OS/ microprocessor support on most nodes Heterogeneous networkHeterogeneous network

Tower of Power 16 PII 300 MHz PCs w/ 256 MB RAM16 PII 300 MHz PCs w/ 256 MB RAM Myrinet and Fast Ethernet Switched NetworksMyrinet and Fast Ethernet Switched Networks AMS Wildforce Reconfigurable Computing EngineAMS Wildforce Reconfigurable Computing Engine

Project Timeline Nov 98Aug 99Feb 99May 99 Kickoff Multiboard API Intervention Free Operation Multiboard Debugger Applications SLAAC-1 & 2 Integration

Requirements (1) Address wide range of applications on cluster and embedded systemsAddress wide range of applications on cluster and embedded systems PortabilityPortability –Must allow application porting without source modification SimplicitySimplicity –Single program for system control

Requirements (2) ExpandabilityExpandability –Support new node types PerformancePerformance –Must keep an acceptable level of performance

Requirements (3) SimplicitySimplicity –Single host program initializes and controls system Host process controls host node, control process runs on othersHost process controls host node, control process runs on others –Standard functions provide unified control of hardware and communication

Requirements (4) ExpandabilityExpandability –Object Oriented Implementation Inherit node class and modify functionsInherit node class and modify functions PerformancePerformance –Zero copy buffers –Recognizes differences between remote and local node to reduce overhead

System Creation Functions ACS_InitializeACS_Initialize –Parses command line. –Initializes globals. ACS_System_CreateACS_System_Create –Allocates nodes and channels. –Creates opaque system object in host program. –Same host program can manage multiple systems. –Nodes and channels are logically numbered in order of creation. –Host is node zero

Memory Access Functions ACS_Read()ACS_Read() –Gets block of memory from (system, node, address, count) into user buffer. ACS_Write()ACS_Write() –Puts block of memory from user buffer to (system, node, address, count). ACS_Copy() –Copies memory from (node1, address1) to (node2, address2) directly. ACS_Interrupt() –Generates an interrupt signal at node.

Streaming Data Functions Each node/system has a set of FIFO buffers.Each node/system has a set of FIFO buffers. Channels connect two FIFO buffers.Channels connect two FIFO buffers. Arbitrary streaming- data topologies supported.Arbitrary streaming- data topologies supported. ACS_Enqueue() –put user data into FIFO ACS_Dequeue() –get user data from FIFO 1 0 FIFO 0 FIFO 1 FIFO 2 FIFO 3 FIFO 0 FIFO 1 FIFO 2 FIFO 3 2 FIFO 0 FIFO 1 FIFO 2 FIFO 3

Performance Monitor Dynamic Topology Display Performance Metrics Playback (future)

ACS Multiboard Debugger Based on Boardscope and Jbits Will provide –Waveforms –State Status –Channel Status Interfaces through SLAAC API

Applications Video/Image processingVideo/Image processing –Real Time Filtering Super Real Time Wireless Channel ModelSuper Real Time Wireless Channel Model 2-D FIR Filter2-D FIR Filter 2-D Wavelet and Image Interpolator2-D Wavelet and Image Interpolator

Deficiencies FIFO LimitationsFIFO Limitations –Too small and slow for efficient bus transfer –Drivers limit I/O performance –Cannot keep board supplied with data to process Closed Board ArchitectureClosed Board Architecture Closed Driver SourceClosed Driver Source Benefits of SLAAC-1 & 2Benefits of SLAAC-1 & 2 –Higher I/O throughput capability –Open Architecture model

Hostless Integration of ACS Node and Myrinet Allows for Communication without Host InterventionAllows for Communication without Host Intervention –Lower latency –More efficient use of bus bandwidth Protocol with LANaiProtocol with LANai –Header fields determine packet destination within a node –DMA transfers initiated by LANai

Future Work Support for RunTime Reconfiguration (RTR)Support for RunTime Reconfiguration (RTR) API implementation for embedded systemsAPI implementation for embedded systems System level management of multiple programsSystem level management of multiple programs

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