Multithreading and Parallelism Quiz

What is a benefit of multithreading in applications?

• Increased process creation time

• Higher memory usage

• Reduced code complexity

• Improved responsiveness

Answer explanation

Multithreading improves responsiveness by allowing an application to perform multiple tasks simultaneously. This means that while one thread is waiting for a resource, others can continue executing, leading to a smoother user experience.

What type of parallelism distributes subsets of the same data across multiple cores?

• Task parallelism

• Data parallelism

• Thread parallelism

• Process parallelism

Answer explanation

Data parallelism involves distributing subsets of the same data across multiple cores, allowing simultaneous processing of data elements. This is distinct from task parallelism, which focuses on executing different tasks concurrently.

Which threading model allows many user-level threads to be mapped to many kernel threads?

• Two-level

• One-to-One

• Many-to-Many

• Many-to-One

Answer explanation

The Many-to-Many threading model allows multiple user-level threads to be mapped to multiple kernel threads, providing flexibility and efficient resource utilization. This is why it is the correct choice.

What is the primary purpose of a thread library?

• To handle user input

• To manage memory allocation

• To optimize CPU usage

• To provide an API for thread management

Answer explanation

The primary purpose of a thread library is to provide an API for thread management, allowing developers to create, synchronize, and manage threads effectively, which is essential for concurrent programming.

Which of the following is a characteristic of user threads?

• Always run in parallel

• Managed by user-level libraries

• Require kernel support

• Managed by the kernel

Answer explanation

User threads are managed by user-level libraries, allowing for efficient context switching without kernel intervention. This distinguishes them from kernel threads, which require kernel support and are managed by the operating system.

What does the Java Executor Framework facilitate?

• Signal handling

• Automatic thread management

• Explicit thread creation

• Memory allocation

Answer explanation

The Java Executor Framework simplifies concurrent programming by managing thread creation and execution automatically, allowing developers to focus on task implementation rather than thread lifecycle management.

What is the main advantage of using thread pools?

• Faster thread creation

• Lower memory usage

• Easier debugging

• Increased process switching

Answer explanation

The main advantage of using thread pools is faster thread creation. By reusing existing threads, thread pools minimize the overhead associated with creating and destroying threads, leading to improved performance in concurrent applications.

What does fork-join parallelism involve?

• Single-threaded execution

• Joining threads before forking

• Forking multiple tasks and then joining them

• Creating threads without joining

Answer explanation

Fork-join parallelism involves forking multiple tasks to run concurrently and then joining them back together. This allows for efficient use of resources and improved performance, making 'Forking multiple tasks and then joining them' the correct choice.

Which of the following is a feature of Grand Central Dispatch?

• No concurrency primitives

• Single-threaded execution

• Automatic thread creation and destruction

• Manual thread management

Answer explanation

Grand Central Dispatch (GCD) automates thread management, allowing for automatic thread creation and destruction. This feature simplifies concurrency, making it easier for developers to manage tasks without manual intervention.

What is thread-local storage (TLS) used for?

• Sharing data between threads

• Allowing each thread to have its own copy of data

• Managing memory allocation

• Creating global variables

Answer explanation

Thread-local storage (TLS) is used to allow each thread to have its own copy of data, ensuring that data is not shared between threads. This prevents data corruption and ensures thread safety.