Lecture 14: Synchronization 6

Question 1

Monitors:

Answer 1

A high-level synchronization abstraction

Question 2

When thread t calls wait()

Answer 2

t releases object lock
t’s state = BLOCKED
t placed in wait set

Question 3

When thread t calls notify()

Answer 3

a. selects some thread t’ from wait list
b. moves t to entry set
c. state of t:= RUNNABLE (Can again compete for lock)

Question 4

notify()

Answer 4

Selects arbitrary thread from wait set

Question 5

notifyAll ():

Answer 5

Removes ALL threads from wait set and puts them in entry set
Best to use if potentially multiple threads in wait set
(Safe if thread code loops checking conditions)