Java Multithreading and Parallel Programming Masterclass - No-Starve Mutex Problem

The lecture discusses the no starve mutex problem, a multi-threading issue where one thread may monopolize a lock, causing starvation for others. It explains mutexes, critical sections, and how Java's fairness policy can prevent starvation at a performance cost. The solution to the problem, devised by JM Morris, involves a two-room model using semaphores to ensure all threads eventually access the critical section, preventing starvation.

What is the main issue addressed by the no starve mutex problem?

• Deadlock

• Priority inversion

• Starvation

• Race condition

In Java, what does setting the 'fair' parameter to true in ReentrantLock achieve?

• Increases performance

• Ensures fairness in lock acquisition

• Prevents deadlock

• Reduces memory usage

Why is the fairness parameter set to false by default in Java's ReentrantLock?

• To reduce memory usage

• To ensure fairness

• To maximize performance

• To prevent deadlock

What is a characteristic of a weak lock?

• It provides fairness

• It guarantees no starvation

• It does not guarantee lock acquisition

• It is faster than a strong lock

What is the main advantage of using a strong lock?

• It is easier to implement

• It is faster than a weak lock

• It guarantees no starvation

• It uses less memory

Who proposed the solution to the no starve mutex problem?

• Leslie Lamport

• JM Morris

• Tony Hoare

• Edsger Dijkstra

What is the purpose of the two rooms in JM Morris's solution?

• To separate read and write operations

• To reduce memory usage

• To prioritize high-priority threads

• To manage thread transitions and prevent starvation

In the code implementation, what role do semaphores S1 and S2 play?

• They reduce execution time

• They control thread access to rooms

• They manage memory allocation

• They prioritize high-priority threads

What happens when the last thread leaves room 2 in the code implementation?

• S1 is released, allowing new threads into room 2

• S2 is released, allowing new threads into room 1

• The critical section is locked

• All threads are terminated

What is the key idea behind the solution to the no starve mutex problem?

• Using a single room for all threads

• Prioritizing high-priority threads

• Allowing multiple threads to access the critical section simultaneously

• Phased transitions between rooms to manage thread access