Parallel VLSI CAD Algorithms zhuofeng/EE5900Spring2012...¢  Parallel VLSI CAD Algorithms Lecture 1 Introduction

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  • Parallel VLSI CAD Algorithms

    Lecture 1 Introduction Zhuo Feng

    Z. Feng MTU EE5900 Spring 2012Z. Feng MTU EE5900 Spring 20121.1.11

  • ■ Prof. Zhuo Feng ► Office: EERC 513 ► Phone: 487-3116 ► Email: zhuofeng@mtu.edu

    ■ Class Website ■ Class Website ► http://www.ece.mtu.edu/~zhuofeng/EE5900Spring2012.html ► Check the class website for lecture materials, assignments

    and announcementsand announcements

    Schedule■ Schedule ► TR 9:35am-10:50am EERC 218 ► Office hours: TR 4:30pm – 5:30pm or by appointments

    Z. Feng MTU EE5900 Spring 2012Z. Feng MTU EE5900 Spring 20121.1.22

  • Textbook ► Pillage, Rohrer and Visweswariah, Electronic circuit and

    system simulation methods, McGraw-Hill, 1995.

    References ► [1] Various IEEE journal and conference papers: IEEE► [1] Various IEEE journal and conference papers: IEEE

    Trans. on CAD, IEEE/ACM Design Automation Conference, IEEE/ACM Intl. Conf. on CAD, IEEE Trans. on Circuits and Systems.Systems.

    ► [2] Farid Najm, Circuit simulation, Wiley-IEEE Press, 2010. ► [3] Kundert, White and Sangiovanni-Vincentelli, “Steady-

    state methods for simulating analog and microwavestate methods for simulating analog and microwave circuits,” Kluwer, 1990.

    ► [4] Celik, Pileggi and Odabasioglu, “IC interconnect analysis” Kluwer 2002

    Z. Feng MTU EE5900 Spring 2012Z. Feng MTU EE5900 Spring 20121.1.33

    analysis , Kluwer 2002.

  • Topics (tentative) ■ Introduction ■ Brief review of matrix theory, linear algebra and

    numerical methods numerical methods ■ Basic circuit analysis methods (Part 1, Part 2) ■ IC interconnect modeling methodsg ■ Model order reduction techniques (AWE, PRIMA) ■ RF circuit simulation methods ■ Introduction to emerging heterogeneous parallel

    computing platforms ■ Parallel GPU based simulation methods for power ■ Parallel GPU-based simulation methods for power

    delivery networks. ■ Full-chip thermal analysis on GPUs

    Z. Feng MTU EE5900 Spring 2012Z. Feng MTU EE5900 Spring 20121.1.44

    p y ■ Parallel 3D capacitance extraction on GPU

  • ■ Project ► This is a project/research oriented course. ► Research explorations are strongly encouraged. ► Students are expected to read research papers assigned► Students are expected to read research papers assigned

    before lectures and actively participate in class discussions.

    G di■ Grading ► Assignment (course projects): 70% ► Exams: 30%

    ■ No plagiarism !

    Z. Feng MTU EE5900 Spring 2012Z. Feng MTU EE5900 Spring 20121.1.55

  • ■ A plethora of VLSI CAD problems

    Devices, interconnects, circuits, systems, i l l di it l

    Z. Feng MTU EE5900 Spring 2012Z. Feng MTU EE5900 Spring 20121.1.66

    signal, power, analog, digital …..

  • ■ Where are we in the design flow? Specifications

    System-level DesignSystem level Design

    RTL-level Design

    Gate-level DesignTop-down Design

    Bottom-up Verification

    Transistor/Circuit Level

    Electrical & Th l P ti

    Final Verification

    Layout Thermal Properties, Delays, Waveforms, Parasitics Effects, Coupling Noise …

    Z. Feng MTU EE5900 Spring 2012Z. Feng MTU EE5900 Spring 20121.1.77

    Final VerificationCoupling Noise …

  • ■ Why circuit analysis?y y

    ►Performance verification

    ▼A critical step for evaluating expected performance prior to manufacturing

    ▼Simulation is always cheaper and more efficient than actually making the chip

    ▼True more than ever for today’s high manufacturing costs

    Z. Feng MTU EE5900 Spring 2012Z. Feng MTU EE5900 Spring 20121.1.88

  • ■ Why circuit simulation (cont’d) ?

    ► Design optimization/synthesis

    ▼Need to evaluate circuit performances many times in an optimization loop before meeting all the specs

    ▼Can only be practically achieved via simulation (models)

    Circuit Optimizer Meet all specs? ConvergenceCircuit Optimizer

    Update design parameters

    Meet all specs?

    YesNo

    Convergence

    Simulation Engine

    Performance Evaluation

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  • ■ Why models? ► Models are integral parts of system simulation and/or optimization

    Abstract Executable Models

    Abstract Executable Models

    High

    Cycle Accurate Models

    Cycle Accurate Models Speed

    Low

    VHDL/Verilog Models

    VHDL/Verilog Models

    Interconnect Gate Models Interconnect Gate Models

    Cost

    Low Gate ModelsGate Models

    Device ModelsDevice ModelsHigh

    Z. Feng MTU EE5900 Spring 2012Z. Feng MTU EE5900 Spring 20121.1.1010

    High

  • ■ Assessment of simulators

    Accuracy

    Robustness/

    Accuracy

    Robustness/ Applicability

    Runtime Memory

    Runtime Memory

    Accuracy

    Runtime

    Z. Feng MTU EE5900 Spring 2012Z. Feng MTU EE5900 Spring 20121.1.1111

    Runtime Memory

  • ■ Selected Topicsp

    ►Classical circuit simulation methods (SPICE) ▼LU factorization, Newton’s method▼LU factorization, Newton s method

    ▼(Modified) nodal formulation (MNA)

    ▼Nonlinear DC analysisy

    ▼AC analysis

    ▼Linear/nonlinear transient analyses

    ▼SPICE device models

    Z. Feng MTU EE5900 Spring 2012Z. Feng MTU EE5900 Spring 20121.1.1212

  • ■ Many problems are modeled by some form of coupled (nonlinear) first order differential equations(nonlinear) first-order differential equations

    F i it bl thi i ll d i MNA ■ For circuit problems this is usually done using MNA formulation

    

    f(v)i  1v2v 4vR

    3v

    

    Cv  3v

    Z. Feng MTU EE5900 Spring 2012Z. Feng MTU EE5900 Spring 20121.1.1313

  • ■ Write KCL (Kirchoff’s Current Law) at node 1:

    0)()()( 124131    vvf R

    vv dt

    vvdC

    ■ If we do this for all N nodes:

    0))(),(),(( tutxtxF    Xx  )0(

    N dimensional vector of unknown node voltages

    )(tx

    vector of independent sources

    nonlinear operator

    )(tu

    F

    Z. Feng MTU EE5900 Spring 2012Z. Feng MTU EE5900 Spring 20121.1.1414

    nonlinear operatorF

  • How can we solve this set of nonlinear differential equations?

    0))(),(),(( tutxtxF    Xx

     )0(

    ■ Closed-form formula/hand analysis easily b i f iblbecomes infeasible

    ■ Need to develop computer programs (circuit i l t ) t l f th l ti i llsimulators) to solve for the solution numerically

    Z. Feng MTU EE5900 Spring 2012Z. Feng MTU EE5900 Spring 20121.1.1515

  • ■ Selected Topics ► Elmore delay ► Timing simulation ► Intend to evaluate the circuit timing quickly

    ▼ Crucial for large VLSI circuit synthesis/optimization ▼ Provide delay estimation or waveform approximation ▼ o de de ay est at o o a e o app o at o

    using easy-to-compute metrics or (approximated) timing simulation

    R4R4

    C4 R1 R2 R3

      44)432(2 432114

    CRCCCR CCCCRTD

     

    C1 C2 C3

    Z. Feng MTU EE5900 Spring 2012Z. Feng MTU EE5900 Spring 20121.1.1616

    44)432(2 CRCCCR 

  • ■ Selected Topics ► Model order reduction

    ► Key drivers for achieving feasible simulation y g ▼ IC interconnect analysis ▼Whole system verification ▼Design space explorationg p p

    MacromodelingFull System Model

    Z. Feng MTU EE5900 Spring 2012Z. Feng MTU EE5900 Spring 20121.1.1717

  • ■ Selected topics ►Parallel CAD

    Courtesy Intel Courtesy AMD Courtesy TI

    Z. Feng MTU EE5900 Spring 2012Z. Feng MTU EE5900 Spring 20121.1.1818

  • GPU Computing for CADGPU Computing for CAD ■ Dedicated for graphics rendering

    CPUVideo Out CPU (host)

    GPU is connected to MCH via 16x PCI-Expressvia 16x PCI-Express

    Z. Feng MTU EE5900 Spring 2012Z. Feng MTU EE5900 Spring 20121.1.1919

  • ■ Reading assignments ► T tb k Ch t 1 d 2► Textbook. Chapters 1 and 2

    ■ History of SPICEy ► CANCER at UCB: Computer Analysis of Nonlinear Circuits

    Excluding Radiation

    ► Government project SCEPTRE: System for Circuit Evaluation and Prediction of Transient Radiation Effects

    ► CANCER evolved to SPICE: Simulation Program with Integrated Circuit Emphasis

    ► SPICE became the industry standard

    Z. Feng MTU EE5900 Spring 2012Z. Feng MTU EE5900 Spring 20121.1.2020

  • ■ SPICE overview ►N equations in terms of N unknown Node voltages ►More generally using modified nodal analysis

    G(v)i  vv vR 

    G(v)i  1v2v 4v C

    R

    v  

    3v

    Z. Feng MTU EE5900 Spring 2012Z. Feng MTU EE5900 Spring 20121.1.2121

  • Time Domain Equations at node 1:Time Domain Equations at node 1:

    0)()()( 124131    vvG R

    vv dt

    vvdC

     If we do this for all N nodes:

    0))(),(),(( tutxtx