Multithreading

Question 1

What does the preprocessor do in the program creation process?

Answer 1

It processes directives (e.g., macros, file inclusions, conditional compilations) to transform the source code before compilation.

Question 2

What is the role of the compiler in program creation?

Answer 2

The compiler translates source code into machine code by performing syntax and semantic analysis, optimizations, and code generation.

Question 3

What does an assembler do in the program creation process?

Answer 3

It converts assembly language code into machine code by translating mnemonic instructions into binary representations.

Question 4

What is the function of the linker in program creation?

Answer 4

The linker combines object files into a single executable by resolving external symbols and organizing the memory layout.

Question 5

What is a thread?

Answer 5

A thread is the smallest unit of execution within a process, managed by the scheduler.

Question 6

How is parallelism defined in computing?

Answer 6

Parallelism is the simultaneous execution of multiple computations or processes to improve performance.

Question 7

What does concurrency mean in computing?

Answer 7

Ability to manage multiple tasks at the same time and switch between them as needed

Question 8

What is data parallelism?

Answer 8

It is the execution of the same operation concurrently on different pieces of distributed data.

Question 9

What is task parallelism?

Answer 9

Task parallelism is the concurrent execution of different tasks or functions that perform distinct operations independently.

Question 10

What are kernel threads?

Answer 10

Kernel threads are threads managed directly by the operating system, which handles their scheduling and resource allocation.

Question 11

What are user threads?

Answer 11

User threads are threads managed by a user-level library rather than directly by the operating system.

Question 12

What is the many-to-one threading model?

Answer 12

It is a model where many user-level threads are mapped to a single kernel thread.

Question 13

What is the purpose of the many-to-one threading model?

Answer 13

Its purpose is to simplify thread management at the user level.

Question 14

What is one advantage of the many-to-one threading model?

Answer 14

It offers efficient context switching with less overhead.

Question 15

What is one disadvantage of the many-to-one threading model?

Answer 15

A blocking system call can block all threads, and it cannot utilize multiple processors concurrently.

Question 16

What is the one-to-one threading model?

Answer 16

It is a model where each user-level thread is mapped to a unique kernel thread.

Question 17

What is the purpose of the one-to-one threading model?

Answer 17

Its purpose is to allow true parallel execution on multiprocessor systems.

Question 18

What is one advantage of the one-to-one threading model?

Answer 18

It provides better concurrency and true parallelism.

Question 19

What is one disadvantage of the one-to-one threading model?

Answer 19

It increases overhead and consumes more system resources due to managing many kernel threads.

Question 20

What is the many-to-many threading model?

Answer 20

It is a model where many user threads are mapped to many kernel threads.

Question 21

What is the purpose of the many-to-many threading model?

Answer 21

Its purpose is to combine the benefits of user-level and kernel-level threading by providing flexible scheduling.

Question 22

What is one advantage of the many-to-many threading model?

Answer 22

It allows efficient resource use and flexible scheduling of threads.

Question 23

What is one disadvantage of the many-to-many threading model?

Answer 23

Its implementation is more complex and may introduce mapping overhead.

Question 24

What are Pthreads?

Answer 24

Pthreads (POSIX Threads) is a standardized API for creating and managing threads in UNIX-like operating systems.

Question 25

What are threading directives?

Answer 25

They are compiler-specific instructions (such as those used in OpenMP) that guide the compiler in parallelizing code.

Question 26

What is implicit threading?

Answer 26

Implicit threading automatically handles thread creation and workload distribution, reducing the need for explicit thread management by the programmer.

Question 27

What is a thread pool?

Answer 27

A thread pool is a collection of pre-created threads that are available to execute tasks, reducing the overhead of thread creation.

Question 28

What is OpenMP?

Answer 28

OpenMP is an API that supports shared-memory parallel programming in C, C++, and Fortran through compiler directives, runtime routines, and environment variables.

Question 29

What is a signal in computing?

Answer 29

A signal is a notification sent to a process to inform it of an event like an interrupt, exception, or other system condition.

Question 30

What is a synchronous signal?

Answer 30

It is a signal generated as a direct result of a process's actions, such as an arithmetic error.

Question 31

What is an asynchronous signal?

Answer 31

It is a signal generated by external events (e.g., hardware interrupts or user actions) that can occur at any time during execution.

Question 32

What is the default signal handler?

Answer 32

It is the system-provided function that handles signals when no custom handler is specified.

Question 33

What is a user-defined signal handler?

Answer 33

It is a custom function written by the programmer to handle specific signals in a tailored manner.

Question 34

What is thread cancellation?

Answer 34

Thread cancellation is the process of terminating a thread before its natural completion.

Question 35

What is a targeted thread in the context of cancellation?

Answer 35

It is the specific thread chosen to be terminated during a cancellation request.

Question 36

What is asynchronous thread cancellation?

Answer 36

It terminates a thread immediately, regardless of its current state, without waiting for a safe termination point.

Question 37

What is deferred thread cancellation?

Answer 37

It allows a thread to periodically check for cancellation requests at designated safe points before terminating.

Question 38

What is a cancellation point in thread cancellation?

Answer 38

It is a designated point in a thread’s execution where it checks for any pending cancellation requests.

Question 39

What is a cleanup handler in the context of thread cancellation?

Answer 39

It is a function that performs resource deallocation or other necessary cleanup when a thread is cancelled.

Question 40

What is thread local storage?

Answer 40

It provides each thread with its own private storage area, ensuring that data is not shared inadvertently among threads.

Question 41

What is a lightweight process (LWP)?

Answer 41

A lightweight process is similar to a thread; it shares resources with other LWPs but maintains its own execution context for efficiency.

Question 42

What are scheduler activations?

Answer 42

They are a technique that allows the kernel to notify a user-space thread scheduler about events like I/O completions, bridging kernel and user-level thread management.

Question 43

What is an upcall?

Answer 43

It is a callback mechanism where the kernel notifies a user-level process or scheduler about events requiring intervention, such as I/O events.