Vector Processor Architecture
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What is the primary function of scalar registers in a vector computer?

  • To perform vector operations independently
  • To provide input data to vector functional units (correct)
  • To store vector elements temporarily
  • To handle hazards in pipeline architecture

    • What is the characteristic of the vector load/store unit in a pipelined architecture?

  • It can move words between vector registers and memory with a bandwidth of one word per clock cycle (correct)
  • It can only handle scalar loads and stores
  • It can start a new operation every two clock cycles
  • It is not fully pipelined and can cause structural hazards

    • What is the purpose of the control unit in a vector computer?

  • To manage scalar registers and vector registers
  • To handle vector operations in parallel
  • To optimize vector instructions for RISC-V ISA
  • To detect hazards in pipeline architecture (correct)

    • Which of the following is a characteristic of vector functional units in a pipelined architecture?

    <p>Each unit is fully pipelined and can start a new operation on every clock cycle</p> Signup and view all the answers

    What is the purpose of the vector add instruction (vadd) in RISC-V ISA?

    <p>To add elements of V[rs1] and V[rs2] and store the result in V[rd]</p> Signup and view all the answers

    How many general-purpose registers and floating-point registers are there in this particular architecture?

    <p>31 general-purpose registers and 32 floating-point registers</p> Signup and view all the answers

    What is the purpose of the vector load instruction (vld) in RISC-V ISA?

    <p>To load vector register V[rd] from memory starting at address R[rs1]</p> Signup and view all the answers

    What is the significance of the initial latency in the vector load/store unit?

    <p>It is the time required for the unit to start moving words between vector registers and memory</p> Signup and view all the answers

    What is the primary advantage of vector processing in terms of control hazards?

    <p>Elimination of control hazards</p> Signup and view all the answers

    What is the typical number of registers in RV64V vector registers?

    <p>32</p> Signup and view all the answers

    What is the purpose of the switches in the RV64V architecture?

    <p>Connecting vector registers to input/output of vector functional units</p> Signup and view all the answers

    What is the base instruction set for 64-bit RISC-V?

    <p>RV64I</p> Signup and view all the answers

    What is the extension for vector operations in RISC-V?

    <p>V</p> Signup and view all the answers

    What is the primary function of a scalar unit in a vector processor?

    <p>Executing scalar instructions</p> Signup and view all the answers

    What is the typical pipeline architecture of a vector processor?

    <p>Superscalar pipeline</p> Signup and view all the answers

    What is the width of each vector register in RV64V?

    <p>64-bit</p> Signup and view all the answers

    What is the main advantage of vector processors in scientific and engineering applications?

    <p>They can exploit parallelism in large structured data</p> Signup and view all the answers

    What is the characteristic of a single instruction that specifies a large amount of work to be performed?

    <p>CISC approach</p> Signup and view all the answers

    What is the purpose of interleaved memory in vector processing?

    <p>To provide memory access to a whole vector instead of each element at a time</p> Signup and view all the answers

    What is the advantage of using vector instructions in terms of control hazards?

    <p>They eliminate control hazards</p> Signup and view all the answers

    What is the purpose of the dependency verification logic in vector instructions?

    <p>To check data hazards between two vector instructions once per vector operand</p> Signup and view all the answers

    What is the advantage of vector instructions in terms of the complexity of the dependency verification logic?

    <p>It is equal to the complexity of the logic for scalar instructions</p> Signup and view all the answers

    What is the purpose of multimedia extensions in microprocessors?

    <p>To introduce vector processing capabilities</p> Signup and view all the answers

    What is the benefit of using vector instructions in terms of elementary operations?

    <p>They execute more elementary operations in the same control logic's complexity</p> Signup and view all the answers

    What is the purpose of the block ID, number of threads per block, and thread ID in the GPU function?

    <p>To compute the corresponding element index</p> Signup and view all the answers

    In a vectorized loop, what is the purpose of dividing the iteration into two loops?

    <p>To handle iterations that are less than mvl size</p> Signup and view all the answers

    What is the advantage of using a grid with multiple thread blocks in GPU parallel processing?

    <p>To process large datasets in parallel</p> Signup and view all the answers

    What is the purpose of the modulo operation in the MVL code example?

    <p>To find the odd-sized piece of the iteration</p> Signup and view all the answers

    How many elements are executed simultaneously by the SIMD instruction in the example?

    <p>32 elements</p> Signup and view all the answers

    What is the purpose of the thread block configuration in the GPU code?

    <p>To process large datasets in parallel</p> Signup and view all the answers

    What is the advantage of using a vectorized loop in GPU parallel processing?

    <p>To process large datasets in parallel</p> Signup and view all the answers

    What is the purpose of the grid configuration in the GPU code?

    <p>To divide the iteration into multiple thread blocks</p> Signup and view all the answers

    What is the main feature of the instruction 'a * X ~ and Y ~'?

    <p>It is a RISC instruction that performs a large amount of work.</p> Signup and view all the answers

    Why are vector processors particularly useful for scientific and engineering applications?

    <p>Because they operate on large structured data, such as matrices and vectors.</p> Signup and view all the answers

    What is the purpose of interleaved memory in vector processing?

    <p>To provide memory access to a whole vector instead of each element.</p> Signup and view all the answers

    What is the benefit of using vector instructions in terms of control hazards?

    <p>They reduce the number of control hazards.</p> Signup and view all the answers

    Why are multimedia extensions introduced in microprocessors ISA?

    <p>To take advantage of vector processing in multimedia applications.</p> Signup and view all the answers

    What is the main characteristic of vector instructions?

    <p>They operate on a large amount of data.</p> Signup and view all the answers

    What is the advantage of vector instructions in terms of dependency verification logic?

    <p>They require less complex dependency verification logic.</p> Signup and view all the answers

    What is the significance of the parallelism of loops in vector processing?

    <p>It exposes the parallelism of loops to improve performance.</p> Signup and view all the answers

    How many elements are processed at a time by each thread of SIMD instructions in the given example?

    <p>32</p> Signup and view all the answers

    What is the role of the hardware thread block scheduler in CUDA?

    <p>Assigning threads to multithreaded SIMD processors</p> Signup and view all the answers

    How many thread blocks are used in the given example?

    <p>16</p> Signup and view all the answers

    What is the purpose of the hardware thread scheduler in CUDA?

    <p>Picking which thread of SIMD instructions to run each clock cycle</p> Signup and view all the answers

    What is the total number of elements in the grid in the given example?

    <p>8192</p> Signup and view all the answers

    How are the elements divided in the given example?

    <p>16 blocks × 16 threads × 32 elements</p> Signup and view all the answers

    Study Notes

    Vector Processors

    • A vector processor consists of a scalar unit, common pipeline, and vector units, with functional units being vector functional units.
    • In the RISC-V vector instruction set extension (RV64V), both vector and scalar registers have multiple read/write ports to accommodate parallel vector operations.
    • RV64V has 32 vector registers, each 64-bit wide, and a vector register file that provides multiple ports to feed all vector functional units.

    Instruction Set Architecture

    • RISC-V instruction set extension has different versions for different bit sizes: RV32 (32-bit), RV64 (64-bit), and RV128 (128-bit).
    • Standard extensions include: M (integer multiplication and division), A (atomic operations), F (single-precision floating-point), D (double-precision floating-point), G (base and MAFD standard extensions), and V (vector operations).

    Vector Registers and Functional Units

    • Each vector register holds a single vector, and the vector register file provides multiple ports to enable overlap among vector operations.
    • Scalar registers provide data as input to vector functional units and computed addresses to pass to the vector load/store unit.
    • Vector functional units are fully pipelined, able to start a new operation on every clock cycle, and require a control unit to detect hazards.

    Vector Load/Store Unit

    • The vector load/store unit loads and stores vectors to and from memory, is fully pipelined, and handles scalar loads and stores.

    Vector Instructions

    • Vector instructions include: vadd (add elements of two vectors), vsub (subtract elements of two vectors), vdiv (divide elements of two vectors), vld (load vector register from memory).
    • Vector instructions follow the RISC approach, specifying a large amount of work to be performed.

    Applications and Characteristics

    • Vector processors are useful for scientific and engineering applications, simulations, weather forecasts, and multimedia applications.
    • Vector processing benefits from parallelism in loops, which can be exposed by the programmer or compiler through vector instructions.
    • Memory access is adapted to provide access to a whole vector instead of each element at a time, and control hazards are eliminated.

    CUDA Terminology and Grid Concept

    • 1 grid can handle 8192 elements, divided into 16 blocks, each with 16 threads, and each thread handling 32 elements at a time.
    • The hardware thread block scheduler assigns thread blocks to multithreaded SIMD processors.
    • The hardware thread scheduler picks which thread of SIMD instructions to run each clock cycle within a SIMD processor.

    CUDA Code Example

    • The code launches n threads, once per vector element, with 256 threads per thread block in a multithread SIMD processor.
    • The GPU function computes the corresponding element index i based on the block ID, number of threads per block, and the thread ID.
    • The operation of multiplication and addition is performed as long as the index i is within the array.

    Vector Computers and Graphics Processing Units

    • Vector processors are useful for scientific and engineering applications, such as simulations of physical phenomena, weather forecasts, and applications that operate on large structured data.
    • Multimedia applications can also benefit from vector processing, including machine learning algorithms.
    • Vector processors were commercialized even before superscalar processors.

    Main Characteristics of Vector Processors

    • The parallelism of loops can be exposed by the programmer or the compiler through the usage of vector instructions.
    • The memory system is adapted to provide memory access to a whole vector instead of to each element at a time.
    • The hardware only needs to check data hazards between two vector instructions once per vector operand.
    • Control hazards that would arise are eliminated, and the dependency verification logic is almost equal to the one required for scalar instructions.
    • Much more elementary operations are executed in the same control logic's complexity.

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    Description

    This quiz covers the basic architecture of a vector processor, including its components and functional units. It also discusses the advantages of vector processing in terms of control hazards.

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