Threads and Multithreading - multicore programming, multithreading models, thread libraries, implicit threading, threading issues - One Line Questions

1. In the one-to-one multithreading model, what is a potential drawback? — High overhead due to creating a kernel thread for each user thread
2. What is a 'spin lock'? — A lock that causes a thread to busy-wait (spin) until the lock is available
3. What is thread-local storage (TLS)? — A technique where each thread has its own copy of a variable
4. What is a 'critical section' in multithreading? — A block of code that accesses shared resources and must be protected from concurrent access
5. Which of the following best describes a 'task' in task-based parallelism (often used in implicit threading)? — A unit of work that can be executed independently
6. What is starvation in multithreading? — A condition where a thread is perpetually denied access to necessary resources
7. What is a deadlock in the context of multithreading? — A state where two or more threads are blocked forever, each waiting for the other to release a resource
8. What is a 'detached thread' in multithreading? — A thread whose resources are automatically reclaimed upon termination without needing to be joined
9. Which of the following best describes a thread? — A lightweight process sharing resources with other threads in the same process
10. Which of the following is a common synchronization problem that can occur if not managed carefully? — Race condition
11. Which threading issue arises when multiple threads access and modify shared data concurrently, leading to unpredictable results? — Race condition
12. Which threading issue involves threads repeatedly making progress but failing to reach a final goal due to continuous changes in the system state? — Livelock
13. Which of the following is a characteristic of implicit threading? — The creation and management of threads are hidden from the developer
14. In multicore programming, what does 'load balancing' refer to? — Distributing computational work evenly across available cores
15. In the context of multicore programming, what is a common challenge faced by developers? — Efficiently distributing work across multiple cores
16. Which type of threading abstracts thread creation and management away from the programmer, often using libraries or language features? — Implicit threading
17. In the context of POSIX Threads (pthreads), what is a common function for creating a new thread? — pthread_create()
18. Which of the following is a disadvantage of the many-to-one multithreading model? — A blocking system call by one thread blocks all threads
19. What is a potential problem with fine-grained locking (using many locks for small sections of data)? — Increased complexity and potential for deadlock
20. What is the primary advantage of using threads within a single process? — Reduced overhead for context switching compared to processes
21. What is a potential issue with using a large number of kernel threads in the one-to-one model? — High overhead and resource consumption
22. Which of the following is a mechanism to prevent race conditions? — Using a mutex to protect critical sections
23. What is the main limitation of the many-to-one threading model concerning parallelism? — It cannot utilize multiple CPU cores effectively
24. In multicore programming, the challenge of ensuring that multiple threads operate on shared data without corrupting it is known as: — Synchronization
25. Which of the following is a benefit of the one-to-one multithreading model? — Allows one thread to block without blocking others
26. What is a common technique used in implicit threading to manage threads? — Thread pools and task-based parallelism
27. Which threading model is used by default in Java? — It depends on the JVM implementation and the operating system
28. Which model offers a good balance between the overhead of the many-to-one model and the potential resource consumption of the one-to-one model? — Many-to-many
29. A semaphore initialized to 1 can function similarly to which other synchronization primitive? — Mutex
30. Which synchronization primitive is suitable for managing access to a resource that can be used by a limited number of threads concurrently (e.g., a connection pool)? — Semaphore
31. Which programming paradigm is often associated with implicit threading, simplifying concurrent programming? — Functional Programming
32. The many-to-many model attempts to combine the benefits of which other models? — Many-to-one and One-to-one
33. Which multithreading model maps many user-level threads to one or more kernel-level threads? — Many-to-many model
34. Which type of threading allows a large number of user threads to be mapped onto a smaller or equal number of kernel threads? — Many-to-many model
35. In the many-to-one multithreading model, what happens if one user thread performs a blocking system call? — The entire process is blocked, preventing other threads from executing
36. Which thread library operates entirely in user space and does not require kernel support for thread management? — Thread Library (like GNU Portable Threads)
37. What is the primary difference between a thread and a process? — Processes have their own memory space, while threads share the memory space of their parent process.
38. Which of the following is a key component of the OpenMP API for implicit threading in C/C++? — #pragma omp parallel for
39. Which threading issue is characterized by a process not making progress because it is waiting for a resource held by another process that is also waiting? — Deadlock
40. Consider a scenario where Thread A holds Resource 1 and needs Resource 2, while Thread B holds Resource 2 and needs Resource 1. This is a classic example of: — Deadlock
41. What is the main benefit of the one-to-one multithreading model? — Allows concurrency even if one thread makes a blocking system call
42. Which synchronization primitive is often used to ensure that only one thread can access a critical section of code at a time? — Mutex (Mutual Exclusion)
43. Which of the following is an example of a common threading issue related to resource contention? — Deadlock
44. In multicore programming, what is 'granularity' referring to? — The level of parallelism in a program, related to the size of independent tasks
45. Which scenario is most likely to lead to a deadlock? — Threads acquiring locks in a circular wait dependency
46. What is the purpose of `pthread_join()` in POSIX threads? — To allow a thread to wait for another thread to complete its execution
47. What is the role of the 'scheduler' in a user-level threading implementation (like the many-to-one model)? — To schedule user threads onto available kernel threads
48. What is the primary function of a thread library? — To provide an API for creating, managing, and synchronizing threads
49. What is the primary purpose of a thread pool? — To provide a fixed set of worker threads ready to execute tasks
50. What is the purpose of a condition variable? — To signal and wait for specific conditions to be met
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