Producer-Consumer Synchronization

Question 1

Single-slot Producer-Consumer Problem

Single-slot Producer-Consumer Problem

Answer 1

• One Slot: multiple producers and multiple consumers
• removeItem()
• consumeItem()

Question 2

Single-slot Producer-Consumer Problem

Producer Code

Answer 2

slot = 1
item  = 0

while(true) { 
produceItem
down(slot)
fillSlot()
up(item) }

Question 3

Single-slot Producer-Consumer Problem

Consumer Code

Answer 3

slot = 1
item  = 0

while(true) { 
down(item)
removeItem()
up(slot)
consumeItem }

Question 4

Producer-Consumer Problem

Producer-Consumer Problem

Answer 4

• Circular queue (fixed-size buffer)
• Producer: inserts items, blocked when queue is full
• Consumer: removes items, blocked when queue is empty

Question 5

Producer-Consumer Problem

Producer Code

Answer 5

slots = n
items = 0
mutex = 1

down(slots)
mutex_lock(mutex)
buffer[pi] = data
pi = (pi + 1) % n
mutex_unlock(mutex)
up(items)

Question 6

Producer-Consumer Problem

Consumer Code

Answer 6

slots = n
items = 0
mutex = 1

down(items)
mutex_lock(mutex)
result = buffer[ci]
ci = (ci + 1) % n
mutex_unlock(mutex)
up(slots)