Multiprocessor Architectures: A Comprehensive Guide for Computer Architecture Students

Question 1

What does Non-Uniform Memory Access (NUMA) in multiprocessor systems refer to?

Accepted Answer

Varying memory access times based on memory location

Answer

Dedicated memory pools for each processor core

Answer

Shared memory distributed across different nodes

Answer

Exclusive ownership of memory blocks by individual cores

Question 2

What functionality does a crossbar switch provide in a multiprocessor system?

Accepted Answer

Dedicated communication paths between all processors

Answer

Time-division multiplexed communication channels

Answer

Arbitrated access to shared resources

Answer

Virtualized network topology

Question 3

What does hyperthreading enable in multiprocessor systems?

Accepted Answer

Multiple threads to share a single physical core

Answer

Increased clock speed for individual threads

Answer

Enhanced cache performance for each thread

Answer

Reduced power consumption

Question 4

Which memory model guarantees that all memory accesses follow a defined order, regardless of whether they are executed by hardware or software?

Accepted Answer

Sequential consistency

Answer

Total store order

Answer

Partial store order

Answer

No consistency

Question 5

In a message-passing multiprocessor architecture, the communication method used between processors is:

Accepted Answer

Message passing

Answer

Shared memory

Answer

Interrupts

Answer

Cache coherence

Question 6

Which techniques can be used to enhance the performance of memory accesses in a multiprocessor system?

Accepted Answer

Both memory interleaving and multi-level caches

Answer

Memory interleaving only

Answer

Multi-level caches only

Answer

Write buffering only

Question 7

What is the main purpose of a directory-based cache coherence protocol?

Accepted Answer

To maintain a centralized record of cache block states

Answer

To reduce cache coherence messages

Answer

To improve performance of write operations

Answer

To provide error correction in case of data corruption

Question 8

What is the intended purpose of a memory barrier instruction within a multiprocessor architecture?

Accepted Answer

To enforce ordering of memory operations

Answer

To prevent instruction reordering by the compiler

Answer

To synchronize shared memory between processors

Answer

To detect and resolve potential deadlocks

Question 9

In a shared memory multiprocessor architecture, which of the following is true?

Accepted Answer

Data is accessible to all processors.

Answer

Processors do not share a common memory space.

Answer

Synchronization mechanisms are not required.

Answer

Each processor has its own private cache.

Question 10

What is the primary function of a cache coherence protocol in a shared memory system?

Accepted Answer

To maintain data consistency among multiple caches

Answer

To increase the cache hit rate

Answer

To reduce memory access latency

Answer

To prevent deadlocks

Question 11

Which of the following synchronization primitives is used to ensure that only one processor can access a shared resource at a time?

Accepted Answer

Mutex

Answer

Semaphore

Answer

Barrier

Answer

Spin lock

Question 12

In a shared-memory multiprocessor system, which mechanism ensures that all processors have a consistent view of shared data?

Accepted Answer

Cache coherence protocols

Answer

Message passing

Answer

Mutual exclusion locks

Answer

Semaphore protocols

Question 13

Which technique can enhance the performance of shared-memory multiprocessor systems?

Accepted Answer

Reducing cache coherence overhead

Answer

Increasing processor count

Answer

Employing faster memory

Answer

Expanding shared memory size

Question 14

In a message-passing multiprocessor system, what component is responsible for routing messages between processors?

Accepted Answer

Dedicated routing hardware

Answer

Operating system

Answer

Individual processors

Answer

Network interface cards

Question 15

In a multiprocessor system with a hierarchical memory structure, which memory level offers the fastest access?

Accepted Answer

Registers

Answer

Main memory

Answer

Cache memory

Answer

Virtual memory

Question 16

Which multiprocessor architecture utilizes a single shared bus to connect processors and memory?

Accepted Answer

Uniform memory access (UMA)

Answer

Non-uniform memory access (NUMA)

Answer

Scalable shared memory (SSM)

Answer

Clustered shared memory (CSM)

Question 17

In a multiprocessor system with shared memory, which mechanism guarantees the consistency of data?

Accepted Answer

Locks

Answer

Polling

Answer

Interrupts

Question 18

In a shared memory multiprocessor system, which hardware component is responsible for maintaining cache coherence?

Accepted Answer

Cache controller

Answer

Operating system

Answer

Compiler

Answer

Memory controller

Question 19

What is the primary role of a memory controller in a multiprocessor system?

Accepted Answer

Managing access to shared memory

Answer

Performing address translation

Answer

Scheduling processor requests

Answer

Caching memory data

Question 20

What is the main purpose of a snoop filter in a shared memory multiprocessor system?

Accepted Answer

Reducing unnecessary snoop traffic

Answer

Improving cache hit rate

Answer

Enhancing data security

Answer

Preventing cache invalidation

Question 21

What is the primary difference between symmetric and asymmetric multiprocessor systems?

Accepted Answer

Role of processors

Answer

Number of cores

Answer

Processing capability

Answer

Memory organization

Question 22

What is the main goal of cache coherency protocols in multiprocessor systems?

Accepted Answer

Ensuring that all processors have a consistent view of shared data

Answer

Improving cache performance

Answer

Reducing memory latency

Answer

Preventing data corruption

Question 23

Which of the following is a key advantage of multiprocessor architectures?

Accepted Answer

Increased processing power and scalability

Answer

Reduced performance due to resource sharing

Answer

Inefficient use of memory due to data replication

Answer

Simpler hardware design compared to single-processor systems

Question 24

What is the primary distinction between a shared memory and a message-passing architecture in multiprocessor systems?

Accepted Answer

Data sharing mechanism: shared memory vs. message exchange

Answer

Processor communication method: direct memory access vs. message passing

Answer

Number of processors: shared memory supports more processors than message-passing

Answer

Type of memory used: shared memory uses a common pool, while message-passing uses local memory

Question 25

Which of the following cache coherence protocols is commonly employed in multiprocessor systems?

Accepted Answer

MESI (Modified, Exclusive, Shared, Invalid)

Answer

FIFO (First-In-First-Out)

Answer

LRU (Least Recently Used)

Answer

Round-robin

Question 26

Which of the following is NOT considered a significant challenge in designing multiprocessor systems?

Accepted Answer

Optimizing floating-point arithmetic operations

Answer

Ensuring cache coherence and data consistency

Answer

Preventing deadlocks and race conditions

Answer

Balancing workload distribution among processors

Question 27

What is the main advantage of using a NUMA (Non-Uniform Memory Access) architecture in multiprocessor systems?

Accepted Answer

Reduced memory access latency by organizing memory closer to the processors that need it

Answer

Increased processor bandwidth by providing dedicated memory channels

Answer

Minimized cache coherence overhead by eliminating shared caches

Answer

Eliminated shared memory contention by assigning exclusive memory regions to each processor

Question 28

What is the primary purpose of a barrier synchronization in a multiprocessor system?

Accepted Answer

Ensuring that all processors reach a specific point in the program before proceeding

Answer

Preventing race conditions and ensuring data consistency

Answer

Resolving memory conflicts between processors

Answer

Synchronizing input/output (I/O) operations across multiple processors

Question 29

In message-passing architectures, what is the primary communication mechanism employed?

Accepted Answer

Interconnection networks

Answer

Shared memory

Answer

Buses

Answer

Caching

Question 30

What is a central challenge in designing cache coherence protocols for multiprocessor systems?

Accepted Answer

Maintaining consistency of cached data across multiple processors

Answer

Reducing cache misses

Answer

Minimizing hardware overhead

Answer

Improving overall system performance

Question 31

Which characteristic best describes symmetric multiprocessor (SMP) architectures?

Accepted Answer

All processors share the same physical memory

Answer

Processors have dedicated, isolated memory modules

Answer

Communication is exclusively through message passing

Answer

Each processor runs a separate operating system

Question 32

What is the primary function of interprocessor interrupt (IPI) mechanisms in multiprocessor systems?

Accepted Answer

To facilitate signaling of events between processors

Answer

To manage memory access requests

Answer

To synchronize data transfers

Answer

To handle cache misses

Question 33

What is the primary purpose of lock-based synchronization mechanisms in multiprocessor systems?

Accepted Answer

Preventing race conditions that may lead to data corruption

Answer

Improving data consistency

Answer

Reducing resource contention

Answer

Enhancing overall system performance

Question 34

In a shared memory multiprocessor architecture, which of the following is the main concern?

Accepted Answer

Cache coherence

Answer

Deadlock prevention

Answer

Message routing

Answer

Synchronization overhead

Question 35

What is the purpose of a memory consistency model in a shared memory multiprocessor architecture?

Accepted Answer

To ensure that all processors have a consistent view of the shared memory.

Answer

To define how the shared memory is accessed by processors.

Answer

To prevent data corruption due to cache coherency issues.

Answer

To improve the performance of the system.

Question 36

Which of the following is a characteristic of a symmetric multiprocessor (SMP) architecture?

Accepted Answer

All processors share a common memory.

Answer

Each processor has its own local memory.

Answer

The architecture is designed for high scalability.

Answer

The operating system schedules tasks based on the processor's capabilities.

Question 37

What is the main limitation of using a cluster-based multiprocessor architecture?

Accepted Answer

High communication overhead

Answer

Reduced fault tolerance

Answer

Complex software development

Answer

Limited scalability

Question 38

Which protocol ensures data coherency in a shared memory system?

Accepted Answer

Cache Coherence Protocol

Answer

Memory Management Unit (MMU)

Answer

Bus Arbitration Protocol

Answer

Virtual Memory Management Protocol

Question 39

Which is a key benefit of message-passing architecture?

Accepted Answer

Scalability

Answer

Increased bandwidth

Answer

Lower latency

Answer

Reduced complexity

Question 40

Which is a type of message-passing system in which each processor has its own private memory?

Accepted Answer

Distributed Memory System

Answer

Shared Memory System

Answer

Multiprocessor System

Answer

Symmetric Multiprocessor System

Question 41

Which factor does NOT affect the performance of a multiprocessor system?

Accepted Answer

Number of instructions per cycle (IPC)

Answer

Memory bandwidth

Answer

Interconnect topology

Answer

Number of cores

Question 42

Which performance metric measures the efficiency of a multiprocessor system?

Accepted Answer

Speedup

Answer

Latency

Answer

Throughput

Question 43

Which is a potential drawback of using multiprocessor systems?

Accepted Answer

Increased complexity and cost

Answer

Reduced reliability

Answer

Diminished programmability

Answer

Lower power efficiency

Question 44

Which is a current trend in multiprocessor architecture?

Accepted Answer

Heterogeneous computing

Answer

Memory expansion

Answer

Transistor miniaturization

Answer

Decreased clock speed

Question 45

Which of the following cache coherence protocols ensures that all copies of a shared data item in a multiprocessor system are consistent?

Accepted Answer

MESI

Answer

LRU

Answer

FIFO

Question 46

What is the primary advantage of symmetric multiprocessor (SMP) architectures over asymmetric multiprocessor (AMP) architectures?

Accepted Answer

All processors have equal access to shared resources.

Answer

Lower cost of implementation

Answer

Higher scalability

Question 47

What is the main drawback of fine-grained multithreading?

Accepted Answer

High overhead due to frequent context switches.

Answer

Difficulty in debugging

Answer

Limited scalability

Answer

Increased memory requirements

Question 48

What is the purpose of a load-balanced scheduler in a multiprocessor system?

Accepted Answer

Distribute tasks evenly among processors to optimize performance.

Answer

Reduce memory contention

Answer

Enforce cache coherence

Question 49

In a shared memory multiprocessor architecture, what mechanism is primarily used to ensure data consistency across multiple processors accessing the same memory locations?

Accepted Answer

Cache coherence protocols

Answer

Memory interleaving

Answer

Message passing

Answer

Synchronization barriers

Question 50

Which of the following is a significant advantage of message-passing multiprocessor architectures compared to shared memory architectures?

Accepted Answer

Scalability to a large number of processors

Answer

Reduced latency for data access

Answer

Improved cache performance

Answer

Simplified programming

Question 51

In a NUMA (Non-Uniform Memory Access) architecture, which factor does NOT directly influence the latency of memory access?

Accepted Answer

Cache size

Answer

Network topology connecting processors and memory

Answer

Distance of memory location from the processor

Answer

Processor speed

Question 52

In a multiprocessor system, what is the primary purpose of a synchronization barrier?

Accepted Answer

To ensure that all processors have completed a specific set of operations before proceeding further

Answer

To prevent data races by controlling access to shared resources

Answer

To manage cache coherence between processors

Answer

To optimize memory allocation for efficient data access

Question 53

According to Flynn's taxonomy, what classification applies to a multiprocessor system where multiple processors execute multiple instruction streams, each operating on different data sets?

Accepted Answer

MIMD (Multiple Instruction, Multiple Data)

Answer

SIMD (Single Instruction, Multiple Data)

Answer

SISD (Single Instruction, Single Data)

Answer

MISD (Multiple Instruction, Single Data)

Question 54

Which of the following is a commonly used method for managing shared resources in a multiprocessor system, ensuring controlled access and preventing conflicts?

Accepted Answer

Semaphores

Answer

Round-robin scheduling

Answer

Priority queues

Answer

First-come first-served (FCFS) scheduling

Question 55

What is the fundamental difference between a centralized and a distributed shared memory architecture in a multiprocessor system?

Accepted Answer

In a centralized architecture, all memory access is managed by a single memory controller, while in a distributed architecture, memory is spread across multiple controllers, each managing a portion of the shared memory space.

Answer

Centralized architectures are generally faster than distributed architectures due to reduced communication overhead.

Question 56

What is a significant benefit of employing vector processors within multiprocessor architectures?

Accepted Answer

Substantial increase in throughput for vector operations, enhancing performance in tasks that operate on large arrays of data.

Answer

Lower power consumption compared to traditional scalar processors.

Answer

Simplified software development, making it easier to write code for vector operations.

Answer

Improved performance for single-threaded programs due to vectorization.