Final answer:
Spinlocks are a locking mechanism that wastes CPU cycles on busy-waiting, avoids context switch time, and works well on multiprocessor systems. The correct answer to the question is d) All of these.
Step-by-step explanation:
Spinlocks are a type of lock used to manage access to shared resources in concurrent programming environments, particularly in systems with multiple processors. The main characteristics of spinlocks include:
- CPU cycles wasting locks over critical sections of programs. This is because when a thread attempts to acquire a spinlock and finds it already held by another thread, the waiting thread repeatedly checks the lock until it becomes available, thus using CPU cycles.
- Locks that avoid time wastage in context switches compared to other locking mechanisms that put the waiting thread to sleep. Spinlocks keep the thread active but continuously checking for the lock to be released.
- Locks that work better on multiprocessor systems. They are particularly useful in scenarios where the time spent waiting for the lock to become available is expected to be short because preempting a thread might actually take longer than spinning for the lock.
Therefore, the correct answer is d) All of these.