11 - More Synchronization Mechanisms

Question 1

What is a Monitor?

Answer 1

A programming language construct that controls access to shared data

A module that encapsulates
• shared data structures
• and methods that operate on these shared data structures
• synchronization is done between concurrent method invocations

A monitor is a higher-level construct compared to mutexes and semaphores

Question 2

What are some advantages of using Monitors over Semaphores or Mutexes?

Answer 2

• programming with monitors → you test/debug the monitor
• programming with mutexes/semaphores → you test/debug all
code using them

Question 3

What is a Spinlock?

Answer 3

Lightweight alternative to a mutex

Implemented using busy waiting loops

Question 4

Why would one want to use a spinlock?

Answer 4

Wery efficient if you know the wait time will
be very short
• because no re-scheduling required
• only make sense on multi-core/CPU systems