Configurable, reconfigurable, and run-time reconfigurable computing

Outline 1.Introduction –Configurable –Reconfigurable –Run-time reconfigurable 2.Motivating example 3.Tools 4.Software compilers for configurable/reconfigurable systems 5.Multiprocessor complications Modular Design of Configurable Multiprocessor Systems

Introduction Modular Design of Configurable Multiprocessor Systems Which boxes should be chosen to maximize the amount of money while still keeping the overall weight under 15 kg? A multi dimensional problem could consider the density or dimensions of the boxes, the latter a typical packing problem.packing problem (The solution in this case is to choose all of the boxes besides the green one.) Example of a one-dimensional (constraint) knapsack problem:

Configuration Configurable solution: 1.Investigate the best set of boxes to take 2.Take them 3.No more thinking about boxes REconfigurable solution: 1.Investigate the best set of boxes to take 2.Take them for a long time 3.Stop what I’m doing and change everything in my backpack RUN TIME reconfigurable solution: 1.While walking, take the boxes I need and switch for the boxes I don’t need right now. This cost me some time to reconfigure the items in my backpack while walking. Modular Design of Configurable Multiprocessor Systems

Typical system design flow Power? Area? Speed? How can I quickly explore the design architecture and validate it early? Which CPU? Which device? Functionality? Cost? What are the partition trade off’s & how do I verify them? HWSW Spec Project Specification HDLs HW ready  C/ C++

Codesign environment Software-compiled system design flow Power? Area? Speed? Which CPU? Which device? Functionality? Cost? What are the partition trade off’s & how do I verify them? Project Specification Design & VerifySpecify & Verify DSM Spec HW Compile & Verify SystemC, Handel-CC/ C++SW PAL DSM How can I quickly explore the design architecture and validate it early?

What is the essential design question? MAIN QUESTION: How do we make practical systems (large) and meet time-to-market window (small)? ANSWER: Comprehensive co-design tools Modular Design of Configurable Multiprocessor Systems

Motivating Example

Congratulations! You are making a cellular phone. There are many design constraints: –Finite chip area –Finite power consumption –Finite memory (registers, cache, RAM, disk) –Real-time requirements for tasks There are many features: –Camera –Phonebook –Encryption/decryption –DSP –… Modular Design of Configurable Multiprocessor Systems

How do we do co-design for this project? We must make software and hardware for our beloved phone. Which software segments should be implemented in hardware? Do we add one more processor and bus connection, or dedicate that area to a custom instruction? We are OPTIMIZING This is decision problem is also known as the “Knapsack problem” and sometime the “assignment algorithm”, and computers can solve this faster than humans, given a complete and formal problem specification. Modular Design of Configurable Multiprocessor Systems

Tools

Real Configurable System Tools System level co-design from specification to direct implementation –Profiling –Partitioning & trade-off analysis –Co-verification & co-simulation –Higher-level language (HLL) synthesis direct to EDIF or RTL Software-compiled system design –Best time-to-market –Fastest simulation times … VERY FAST –HW/ SW partitioning solution –Seamless HW & SW verification –Reduces cost, risk & time of design –Best QoR & Quality of Design Celoxica

Real Configurable System Tools Modular Design of Configurable Multiprocessor Systems Dimond 2004

Real Configurable System Tools Modular Design of Configurable Multiprocessor Systems CoWare Processor Designer

Real Configurable System Tools Modular Design of Configurable Multiprocessor Systems Tensilica

Tradeoffs Modular Design of Configurable Multiprocessor Systems Tensilica

Tradeoffs Modular Design of Configurable Multiprocessor Systems

Configurable processors Modular Design of Configurable Multiprocessor Systems

Configurable processors Modular Design of Configurable Multiprocessor Systems From register file to configurable block

Configurable processors Modular Design of Configurable Multiprocessor Systems Stall for reconfiguration Or maybe stall during execution

Configurable processors Modular Design of Configurable Multiprocessor Systems Not realistic

Techniques Many techniques for finding what to implement as hardware: –Atasu et al. (DAC 03, CODES 05) –Biswas et al. (DATE 05), Cong et al. (FPGA 04) –Clark et al. (MICRO 03, HOT CHIPS 04) –Goodwin and Petkov (CASES 03) –Sun et al. (ICCAD 03), Yu et al. (CASES 04) –Many more… This is an NP-hard problem equivalent to the “largest common sub-graph identification” problem Modular Design of Configurable Multiprocessor Systems

Software compilers for configurable /reconfigurable systems

What do we want from our compiler? Make it easy to: –Add instructions to my processor model –Check if my model will meet my requirements (simulation/ profiling) –Optimize the generated code for small size and fast speed –Compile code on my PC to run on my phone (retargetable) Hide the details of anything I don’t care about: –Break the compiler into frond end, middle part, and a backend Modular Design of Configurable Multiprocessor Systems

What toys do we need? Compiler (front-middle-backend), debugger, simulator, profiler, assembler, linker, operating system, FPGA Modular Design of Configurable Multiprocessor Systems

What are some common compilers? GCC (Java, Ada, C, C++, has open-MP, popular, optimizing) LCC (Small code size) Trimaran MIMOLA RECORD CoSy LLVM Modular Design of Configurable Multiprocessor Systems

Multiprocessor complications Modular Design of Configurable Multiprocessor Systems

Configurable Interconnect Design Flow Modular Design of Configurable Multiprocessor Systems

WISHBONE Datasheet WISHBONE specification requires that each component has a datasheet Modular Design of Configurable Multiprocessor Systems Example from WISHBONE B.3

Network Specification Modular Design of Configurable Multiprocessor Systems

Example Interconnect Modular Design of Configurable Multiprocessor Systems

Life looks simple at first Modular Design of Configurable Multiprocessor Systems

But life is complicated Modular Design of Configurable Multiprocessor Systems

Questions? Thank You