1. What is the primary benefit of pipelining in instruction execution?
Options:
- A) Increased throughput
B) Reduced instruction count
C) Off-chip data access
D) All of the above - Correct Answer: A) Increased throughput
- Explanation: Pipelining enables multiple instruction stages to execute simultaneously, thereby improving the throughput of the CPU.
2. Which type of memory access allows instructions to lie in the cache?
- Options:
A) Direct mapped
B) Fully associative
C) Set associative
D) None of the above - Correct Answer: B) Fully associative
- Explanation: Fully associative mapping provides the flexibility to store instructions in any cache line, improving the likelihood of cache hits.
3. How do interleaves work to improve system performance?
- Options:
A) By increasing the frequency of DRAM operations
B) By monitoring the status of cache memory
C) By ensuring data is readily available when needed
D) By increasing the number of memory modules - Correct Answer: D) By increasing the number of memory modules
- Explanation: Memory interleaving distributes data across multiple memory modules to allow parallel access, reducing latency and improving performance.
4. What is the primary function of a write buffer?
- Options:
A) To store instructions for the CPU to execute
B) To minimize the frequently visited data
C) To store data temporarily before writing to main memory
D) To prefetch data from memory into the cache - Correct Answer: C) To store data temporarily before writing to main memory
- Explanation: A write buffer temporarily holds data that needs to be written to memory, enabling the CPU to continue execution without waiting for the memory write to complete.
5. What is a commonly used technique to improve performance in a multi-core processor?
- Options:
A) Cache memory
B) Virtual memory
C) Hardware threads
D) Parallel processing - Correct Answer: D) Parallel processing
- Explanation: Parallel processing allows multiple cores to execute tasks simultaneously, leveraging the multi-core architecture for better performance.
6. What happens when there is a cache miss in a write-back cache?
- Options:
A) The data is fetched from the main memory and loaded into the cache.
B) The data is written directly to the main memory.
C) Cache is disabled.
D) The processor waits until the data is written to the main memory. - Correct Answer: A) The data is fetched from the main memory and loaded into the cache.
- Explanation: On a cache miss, the required data is fetched from main memory and stored in the cache for future access.
7. What is the main goal of "software memory optimization"?
- Options:
A) To increase CPU frequency
B) To minimize power consumption
C) To enhance data access speed and CPU performance
D) All of the above - Correct Answer: C) To enhance data access speed and CPU performance
- Explanation: Software memory optimization focuses on techniques like minimizing cache misses and improving memory layout to boost data access speed and overall CPU performance.
8. Which architecture is best suited for parallel processing?
- Options:
A) Von Neumann architecture
B) RISC architecture
C) Parallel Reduced Instruction Set Computing architecture
D) Harvard architecture - Correct Answer: C) Parallel Reduced Instruction Set Computing architecture
- Explanation: This architecture is specifically designed for parallel processing by simplifying instruction sets and enabling efficient parallel execution.
9. Which of the following techniques is employed to improve performance on a multi-core system?
- Options:
A) Threading
B) Multitasking
C) It reduces both power consumption and significantly.
D) It enhances data access speed and CPU performance. - Correct Answer: A) Threading
- Explanation: Threading allows programs to utilize multiple cores effectively by running threads concurrently.
10. To CPU memory access, what type of memory blocks would be accessed?
- Options:
A) Programming memory
B) Cache memory
C) Main memory
D) Virtual memory - Correct Answer: B) Cache memory
- Explanation: The CPU first checks the cache memory for data because it is faster to access than main memory.
11.What is the role of a sector register in vector processors?
- Options:
A) To manage loop operations
B) To keep track of memory allocation
C) To ensure streamlined data flow
D) To reduce cache misses - Correct Answer: C) To ensure streamlined data flow
- Explanation: A sector register in vector processors helps manage the execution of vector operations by ensuring a continuous flow of data during execution.
12. What is the primary benefit of pipelining in regular architecture?
- Options:
A) Increased instruction count
B) Increased throughput
C) Reduced latency
D) Improved memory access - Correct Answer: B) Increased throughput
- Explanation: Pipelining increases throughput by allowing multiple instruction stages to be executed simultaneously.
13. What does SIMD stand for in the context of parallel computing?
- Options:
A) Single Instruction Multiple Duty
B) Single Instruction Multiple Data
C) Special Instruction Multiple Duty
D) Single Instruction Multiple Devices - Correct Answer: B) Single Instruction Multiple Data
- Explanation: SIMD enables parallel processing by performing the same operation on multiple data points simultaneously.
14. What is loop unrolling in vector software optimization?
- Options:
A) Rewriting loops to perform multiple iterations per cycle to increase parallelism
B) Breaking loops into smaller loops to reduce cache misses
C) Combining small loops into a single loop to increase memory efficiency
D) Using compiler optimizations to automatically restructure loops - Correct Answer: A) Rewriting loops to perform multiple iterations per cycle to increase parallelism
- Explanation: Loop unrolling optimizes loops by reducing the overhead of loop control and increasing the number of operations per iteration.
15.What is cache pipelining?
- Options:
A) A technique to increase cache access speed
B) A method of handling multiple cache accesses in parallel
C) A process of organizing cache data in multiple stages
D) All of the above - Correct Answer: D) All of the above
- Explanation: Cache pipelining improves performance by handling multiple stages of cache access simultaneously, increasing access speed and parallelism.
16. What is the purpose of a write buffer in a cache?
- Options:
A) To store read data before it is written to the memory
B) To hold write data before it is written to the memory
C) To store cache hits
D) None of these - Correct Answer: B) To hold write data before it is written to the memory
- Explanation: Write buffers temporarily store data before transferring it to main memory, improving the efficiency of write operations.
17. What is a multilevel cache?
- Options:
A) A cache that operates with multiple stages of data fetching
B) A cache with multiple write buffers
C) A cache with more than one level of memory hierarchy
D) A cache that can store different types of data - Correct Answer: C) A cache with more than one level of memory hierarchy
- Explanation: Multilevel caches (L1, L2, L3) enhance performance by organizing memory access into multiple hierarchies, reducing access times.
18. Which type of prefetching loads data in parallel?
- Options:
A) Hardware prefetching
B) Software prefetching
C) Both A and B
D) None of these - Correct Answer: C) Both A and B
- Explanation: Hardware prefetching automatically predicts data needs, while software prefetching involves compiler or programmer instructions.
19. How does prefetching affect cache hit rates?
- Options:
A) It increases the hit rate by ensuring that data is available when needed
B) It decreases the hit rate by evicting useful data from the cache
C) It has no effect on the hit rate
D) It improves cache coherence - Correct Answer: A) It increases the hit rate by ensuring that data is available when needed
- Explanation: Prefetching loads data into the cache before it is accessed, increasing the likelihood of a cache hit.
20. In a victim cache, which of the following is typically stored?
- Options:
A) Data that was recently evicted from the main cache
B) Data that is frequently written to memory
C) Instructions for the next CPU cycle
D) Cache coherence information - Correct Answer: A) Data that was recently evicted from the main cache
- Explanation: A victim cache temporarily stores evicted cache lines to reduce the cost of cache misses.
21. What is the primary feature of non-blocking caches?
- Options:
A) They allow cache misses to be handled without blocking the CPU
B) They eliminate cache coherence issues in processing instructions
C) They require fewer memory accesses
D) They improve data locality - Correct Answer: A) They allow cache misses to be handled without blocking the CPU
- Explanation: Non-blocking caches enable the CPU to continue executing instructions during a cache miss.
22. Which of the following is a common GPU optimization technique for improving memory performance?
- Options:
A) Cache coherence
B) Memory coalescing
C) Hardware prefetching
D) Data forwarding - Correct Answer: B) Memory coalescing
- Explanation: Memory coalescing aligns memory accesses to reduce memory latency and improve GPU performance.
23. Which of the following best describes a vector processor?
- Options:
A) A processor that ensures a single instruction on a single data element
B) A processor that is used only for scientific computing tasks
C) A processor that is optimized for cache management
D) A processor that executes the same instruction on multiple data elements in parallel - Correct Answer: D) A processor that executes the same instruction on multiple data elements in parallel
- Explanation: Vector processors use SIMD to process multiple data points simultaneously, enhancing computational speed.
24. Which of the following is NOT a feature of vector software?
- Options:
A) Automatic vectorization of loops
B) Use of data parallelism
C) Minimization of memory accesses
D) Sequential processing of data - Correct Answer: D) Sequential processing of data
- Explanation: Vector software relies on parallelism, not sequential processing, for improved performance.
25.What is the primary purpose of non-blocking caches in modern processors?
- Options:
A) To store only write-back data
B) To allow for out-of-order execution by allowing the processor to continue processing other instructions while waiting for cache misses
C) To implement cache coherence protocols
D) To prevent cache pollution - Correct Answer: B) To allow for out-of-order execution by allowing the processor to continue processing other instructions while waiting for cache misses
- Explanation: Non-blocking caches let the CPU handle other tasks during a cache miss, supporting out-of-order execution and improving efficiency.
26. What is the main advantage of non-blocking caches in a multi-threaded environment?
- Options:
A) Increased cache hit rate
B) Reduced blocking between threads while waiting for cache misses
C) Simplified cache coherence
D) Reduced power consumption - Correct Answer: B) Reduced blocking between threads while waiting for cache misses
- Explanation: Non-blocking caches prevent threads from stalling due to cache misses, enhancing parallel performance in multi-threaded environments.
27. What is the advantage of using loop unrolling in vector software optimization?
- Options:
A) It reduces the loop overhead by increasing the number of operations per loop iteration
B) It minimizes the number of cache accesses required
C) It reduces the total number of loops in the program
D) It increases memory bandwidth usage - Correct Answer: A) It reduces the loop overhead by increasing the number of operations per loop iteration
- Explanation: Loop unrolling reduces the overhead associated with looping constructs, improving performance by executing more operations per iteration.
28. How do compilers optimize vectorized loops?
- Options:
A) By parallelizing loops to use SIMD instructions
B) By eliminating unnecessary branching
C) By reordering instructions for better memory locality
D) All of the above - Correct Answer: D) All of the above
- Explanation: Compilers use a combination of techniques, including parallelization, branch elimination, and memory locality optimization, to enhance vectorized loop performance.
29. What is the primary role of memory caches in a multi-core processor?
- Options:
A) To manage data coherence
B) To reduce access time to frequently accessed data
C) To store large datasets for faster processing
D) To manage data consistency - Correct Answer: B) To reduce access time to frequently accessed data
- Explanation: Memory caches store frequently accessed data close to the processor, reducing access latency and improving overall performance.
30. Which of the following is NOT a common optimization in vector software?
- Options:
A) Loop unrolling
B) Minimization of memory accesses
C) Sequential data processing
D) Parallelization - Correct Answer: C) Sequential data processing
- Explanation: Vector software optimization focuses on parallelizing tasks and reducing overheads like memory accesses, not sequential processing.
31. Which type of memory is optimized in GPUs for high throughput?
- Options:
A) Global memory
B) Shared memory
C) Local memory
D) Constant memory - Correct Answer: B) Shared memory
- Explanation: Shared memory in GPUs is on-chip and provides faster access than global memory, which is optimized for high throughput.
32. What is the main advantage of using SIMD instructions?
- Options:
A) They reduce the amount of data processing
B) They improve the efficiency of executing the same operation on large datasets
C) They simplify memory management using single data multiple instructions at a time
D) They allow for out-of-order execution of multiple datasets - Correct Answer: B) They improve the efficiency of executing the same operation on large datasets
- Explanation: SIMD instructions are designed for data-level parallelism, processing multiple data points with a single instruction.
33. Which of the following is true about coarse-grained multithreading?
- Options:
A) It switches between threads after each instruction
B) It is most efficient when there are many independent threads
C) It switches between threads in a fine-grained manner
D) It switches between threads after a long delay or on a thread's stall - Correct Answer: D) It switches between threads after a long delay or on a thread's stall
- Explanation: Coarse-grained multithreading switches threads only during significant delays, such as cache misses.
34. Which of the following defines sequential consistency in the context of parallel programming?
- Options:
A) The order of execution of threads is deterministic
B) Threads are executed concurrently, but operations appear as if they are executed one after the other
C) Each thread operates independently with no synchronization
D) The program execution order is controlled by the operating system - Correct Answer: B) Threads are executed concurrently, but operations appear as if they are executed one after the other
- Explanation: Sequential consistency ensures a coherent result where operations appear in a serialized manner, even if threads execute concurrently.
35. Which of the following is true about sequential consistency?
- Options:
A) It requires that all threads execute their operations in a strictly sequential order
B) It guarantees that the result of parallel execution is the same as some sequential execution order
C) It allows threads to execute operations in any order without synchronization
D) It requires that threads be executed in a strict round-robin order - Correct Answer: B) It guarantees that the result of parallel execution is the same as some sequential execution order
- Explanation: Sequential consistency provides a model where parallel execution behaves like a sequential order for correctness.
36. Which of the following is true about the use of locks in parallel programming?
- Options:
A) Locks slow down single threads accessing shared resources simultaneously
B) Locks guarantee that threads will execute in exactly the same order every time
C) Locks can lead to deadlock if not managed carefully
D) Locks are only used to synchronize threads in a multi-core environment - Correct Answer: C) Locks can lead to deadlock if not managed carefully
- Explanation: Locks are crucial for synchronization but must be used carefully to avoid issues like deadlocks.
37. What problem do locks help solve in parallel programming?
- Options:
A) Optimizing memory bandwidth usage
B) Ensuring that only one thread accesses a shared resource at a time
C) Increasing the number of threads that can be executed simultaneously
D) Decreasing the cache miss rate in multithreaded applications - Correct Answer: B) Ensuring that only one thread accesses a shared resource at a time
- Explanation: Locks prevent race conditions by ensuring exclusive access to shared resources.
38. Which of the following is an example of a lock in parallel programming?
- Options:
A) Semaphore
B) Thread pool
C) Thread context switching
D) Cache coherence protocol - Correct Answer: A) Semaphore
- Explanation: Semaphores are synchronization primitives used to control access to shared resources.
39. What is the key difference between shared memory and private memory in GPU programming?
- Options:
A) Shared memory is faster but limited in size, while private memory is slower but larger
B) Private memory is shared among all threads, while shared memory is specific to each thread - Correct Answer: A) Shared memory is faster but limited in size, while private memory is slower but larger
- Explanation: Shared memory is on-chip and designed for fast access by threads in a block, whereas private memory is allocated per thread and slower.