COARSE GRAINED RECONFIGURABLE ARCHITECTURES

04/18/2014

Aditi Sharma

Dhiraj Chaudhary

Pruthvi Gowda

Rachana Raj Sunku

DAY - 1

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Outline• Introduction • Motivation• Architectures

• MATRIX• RaPiD• RAW• CHESS• DReAM

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Reconfigurable architecture

Fine Grained Coarse Grained

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Reconfigurable Architectures • Fine Grained Architecture

• Coarse Grained Architecture

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Processing Elements

Fine Grained Reconfigurable Architecture (FPGA)

Coarse Grained Reconfigurable Architecture

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Motivation• Disadvantages of Fine Grained Architecture?

• Large routing area (80% of chip area)• Large volume of configuration data• Low area efficiency for arithmetic operations• Reduced clock speed and bandwidth

• Advantages of Coarse Grained Architecture?• Lesser number of PE’s so Placement and Routing problem is less

complex and is much faster• Lesser area of chip devoted to routing and configuration context.• Low power consumption• Fast reconfiguration

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Coarse Grained Architectures• MATRIX• RaPiD• RAW• CHESS• DReAM

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MATRIX- Multiple Alu archiTecture with Reconfigurable Interconnect eXperiment

• Developed at MIT by Andre DeHon in 1996.• Designed for general purpose applications.

Then why not use general purpose processor??

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What is reconfigurable in MATRIX?• Instruction Stores• Control Elements• Data Stores• Interconnections

What else you need??

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MATRIX - Basic Functional Unit (BFU)

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Mirsky, E., & DeHon, A. (1996, April). MATRIX: a reconfigurable computing architecture with configurable instruction distribution and deployable resources. In FPGAs for Custom Computing Machines, 1996. Proceedings. IEEE Symposium on (pp. 157-166). IEEE.

MATRIX - Interconnection Network

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Mirsky, E., & DeHon, A. (1996, April). MATRIX: a reconfigurable computing architecture with configurable instruction distribution and deployable resources. In FPGAs for Custom Computing Machines, 1996. Proceedings. IEEE Symposium on (pp. 157-166). IEEE.

MATRIX - Switch/Port Architecture

• Different modes of MATRIX port:• Static Value mode• Static Source mode• Dynamic Source mode

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Mirsky, E., & DeHon, A. (1996, April). MATRIX: a reconfigurable computing architecture with configurable instruction distribution and deployable resources. In FPGAs for Custom Computing Machines, 1996. Proceedings. IEEE Symposium on (pp. 157-166). IEEE.

MATRIX Application Example: FIR

• Sample values are passed through first row

• Produces results every 2 clock cycles

• Needs 4K cells to implement

• Area Comparison:• MATRIX takes 58Mλ2• FPGA takes up to125Mλ2

for decent performance.

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Mirsky, E., & DeHon, A. (1996, April). MATRIX: a reconfigurable computing architecture with configurable instruction distribution and deployable resources. In FPGAs for Custom Computing Machines, 1996. Proceedings. IEEE Symposium on (pp. 157-166). IEEE.

RaPiD - Introduction• ReconfigurAble PIpelined Datapath• Designed at University of Washington in 1996• Coarse grained field programmable architecture for

constructing deep computational pipelines• Optimized for highly repetitive, computation-intensive

tasks• Motivation

• Compile regular computations into an application specific datapath and the program for controlling that datapath

• Configurable computing performance - close to ASIC• Flexibility – close to General Purpose Processor

• Suitable for DSP Applications

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RaPiD - Emulator

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Fisher, Chris, et al. "An emulator for exploring RaPiD configurable computing architectures.“Field-Programmable Logic and Applications. Springer Berlin Heidelberg, 2001.

RaPiD – Block Diagram

RaPiD Architecture Block Diagram

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Cronquist, Darren C., et al. "Architecture design of reconfigurable pipelined datapaths.“Advanced Research in VLSI, 1999. Proceedings. 20th Anniversary Conference on. IEEE, 1999.

RaPiD – Basic Cell

The Basic Cell of RaPiD-1

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Cronquist, Darren C., et al. "Architecture design of reconfigurable pipelined datapaths.“Advanced Research in VLSI, 1999. Proceedings. 20th Anniversary Conference on. IEEE, 1999.

RaPiD – Functional Unit

Generic Functional Unit

Configurable Delay

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Cronquist, Darren C., et al. "Architecture design of reconfigurable pipelined datapaths.“Advanced Research in VLSI, 1999. Proceedings. 20th Anniversary Conference on. IEEE, 1999.

RaPiD – Interconnect

Interconnect Between FU and Buses

Bus Connector

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1. Ebeling, Carl, Darren C. Cronquist, and Paul Franklin. "RaPiD—Reconfigurable pipelined datapath.“2. Cronquist, Darren C., et al. "Architecture design of reconfigurable pipelined datapaths." 

RaPiD – Local Memory

Local Memory

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Ebeling, Carl, Darren C. Cronquist, and Paul Franklin. "RaPiD—Reconfigurable pipelined datapath.“Field-Programmable Logic Smart Applications, New Paradigms and Compilers. Springer Berlin Heidelberg, 1996.

RaPiD Application Example: FIR

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Algorithm for FIR Filter

Ebeling, Carl, et al. "Mapping applications to the RaPiD configurable architecture." Field-Programmable Custom Computing Machines, 1997. Proceedings., The 5th Annual IEEE Symposium on. IEEE, 1997.

RaPiD Application Example: FIR

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One cell of the FIR Filter

Ebeling, Carl, et al. "Mapping applications to the RaPiD configurable architecture." Field-Programmable Custom Computing Machines, 1997. Proceedings., The 5th Annual IEEE Symposium on. IEEE, 1997.

RaPiD – Performance• High performance for computationally intensive tasks• RaPiD is low-powered

• Local Communication, distributed memories, clock disabling

• It can be a closely coupled co-processor

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Cronquist, Darren C., et al. "Architecture design of reconfigurable pipelined datapaths.“Advanced Research in VLSI, 1999. Proceedings. 20th Anniversary Conference on. IEEE, 1999.

RaPiD – Issues• Not suited for tasks that are

• unstructured• not highly repetitive• control flow strongly depends on the data

• Underutilization of Resources• It is not clear how RaPiD can be coupled to a generic

RISC processor

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