1. The Producer-Consumer Problem OR, The Bounded-Buffer Problem

2. count N 4 buffer Initial State while (TRUE) {N 4
buffer
while (TRUE) {
int item = produce_item();
if (count == N) {
sleep(); }
insert_item(item);
count = count + 1;
if (count == 1) {
wakeup(consumer);
while (TRUE) {
if (count == 0) {
sleep(); }
int item = remove_item();
count = count - 1;
if (count == N - 1) {
wakeup(producer);
process_item(item);
Producer
Consumer

3. count N 4 buffer First, the producer… while (TRUE) {N 4
buffer
while (TRUE) {
int item = produce_item();
if (count == N) {
sleep(); }
insert_item(item);
count = count + 1;
if (count == 1) {
wakeup(consumer);
while (TRUE) {
if (count == 0) {
sleep(); }
int item = remove_item();
count = count - 1;
if (count == N - 1) {
wakeup(producer);
process_item(item);
Producer
Consumer

4. count N 4 buffer ■ while (TRUE) { int item = produce_item();N 4
buffer ■
while (TRUE) {
int item = produce_item();
if (count == N) {
sleep(); }
insert_item(item);
count = count + 1;
if (count == 1) {
wakeup(consumer);
while (TRUE) {
if (count == 0) {
sleep(); }
int item = remove_item();
count = count - 1;
if (count == N - 1) {
wakeup(producer);
process_item(item);
Producer
Consumer

5. count N 4 buffer ■ while (TRUE) { int item = produce_item();N 4
buffer ■
while (TRUE) {
int item = produce_item();
if (count == N) {
sleep(); }
insert_item(item);
count = count + 1;
if (count == 1) {
wakeup(consumer);
while (TRUE) {
if (count == 0) {
sleep(); }
int item = remove_item();
count = count - 1;
if (count == N - 1) {
wakeup(producer);
process_item(item);
Producer
Consumer

6. count N 4 buffer ■ while (TRUE) { int item = produce_item();N 4
buffer ■
while (TRUE) {
int item = produce_item();
if (count == N) {
sleep(); }
insert_item(item);
count = count + 1;
if (count == 1) {
wakeup(consumer);
while (TRUE) {
if (count == 0) {
sleep(); }
int item = remove_item();
count = count - 1;
if (count == N - 1) {
wakeup(producer);
process_item(item);
Producer
Consumer

7. count 1 N 4 buffer ■ while (TRUE) { int item = produce_item();
if (count == N) {
sleep(); }
insert_item(item);
count = count + 1;
if (count == 1) {
wakeup(consumer);
while (TRUE) {
if (count == 0) {
sleep(); }
int item = remove_item();
count = count - 1;
if (count == N - 1) {
wakeup(producer);
process_item(item);
Producer
Consumer

8. count 1 N 4 buffer ■ while (TRUE) { int item = produce_item();
if (count == N) {
sleep(); }
insert_item(item);
count = count + 1;
if (count == 1) {
wakeup(consumer);
while (TRUE) {
if (count == 0) {
sleep(); }
int item = remove_item();
count = count - 1;
if (count == N - 1) {
wakeup(producer);
process_item(item);
Producer
Consumer

9. count 1 N 4 buffer ■ while (TRUE) { int item = produce_item();
if (count == N) {
sleep(); }
insert_item(item);
count = count + 1;
if (count == 1) {
wakeup(consumer);
while (TRUE) {
if (count == 0) {
sleep(); }
int item = remove_item();
count = count - 1;
if (count == N - 1) {
wakeup(producer);
process_item(item);
Producer
Consumer

10. count 1 N 4 buffer ■ while (TRUE) { int item = produce_item();
if (count == N) {
sleep(); }
insert_item(item);
count = count + 1;
if (count == 1) {
wakeup(consumer);
while (TRUE) {
if (count == 0) {
sleep(); }
int item = remove_item();
count = count - 1;
if (count == N - 1) {
wakeup(producer);
process_item(item);
Producer
Consumer

11. count 1 N 4 buffer ■ while (TRUE) { int item = produce_item();
if (count == N) {
sleep(); }
insert_item(item);
count = count + 1;
if (count == 1) {
wakeup(consumer);
while (TRUE) {
if (count == 0) {
sleep(); }
int item = remove_item();
count = count - 1;
if (count == N - 1) {
wakeup(producer);
process_item(item);
Producer
Consumer

12. Similarly…

13. count 4 N 4 buffer ■ ■ ■ ■ ■ while (TRUE) { int item = produce_item();
if (count == N) {
sleep(); }
insert_item(item);
count = count + 1;
if (count == 1) {
wakeup(consumer);
while (TRUE) {
if (count == 0) {
sleep(); }
int item = remove_item();
count = count - 1;
if (count == N - 1) {
wakeup(producer);
process_item(item);
Producer
Consumer

14. count 4 N 4 buffer ■ ■ ■ ■ ■ while (TRUE) { int item = produce_item();
if (count == N) {
sleep(); }
insert_item(item);
count = count + 1;
if (count == 1) {
wakeup(consumer);
while (TRUE) {
if (count == 0) {
sleep(); }
int item = remove_item();
count = count - 1;
if (count == N - 1) {
wakeup(producer);
process_item(item);
Producer
Consumer

15. count 4 N 4 buffer ■ ■ ■ ■ ■ Now, the consumer… while (TRUE) {
int item = produce_item();
if (count == N) {
sleep(); }
insert_item(item);
count = count + 1;
if (count == 1) {
wakeup(consumer);
while (TRUE) {
if (count == 0) {
sleep(); }
int item = remove_item();
count = count - 1;
if (count == N - 1) {
wakeup(producer);
process_item(item);
Producer
Consumer

16. count 4 N 4 buffer ■ ■ ■ ■ ■ while (TRUE) { int item = produce_item();
if (count == N) {
sleep(); }
insert_item(item);
count = count + 1;
if (count == 1) {
wakeup(consumer);
while (TRUE) {
if (count == 0) {
sleep(); }
int item = remove_item();
count = count - 1;
if (count == N - 1) {
wakeup(producer);
process_item(item);
Producer
Consumer

17. count 3 N 4 buffer ■ ■ ■ ■ ■ while (TRUE) { int item = produce_item();
if (count == N) {
sleep(); }
insert_item(item);
count = count + 1;
if (count == 1) {
wakeup(consumer);
while (TRUE) {
if (count == 0) {
sleep(); }
int item = remove_item();
count = count - 1;
if (count == N - 1) {
wakeup(producer);
process_item(item);
Producer
Consumer

18. count 3 N 4 buffer ■ ■ ■ ■ ■ while (TRUE) { int item = produce_item();
if (count == N) {
sleep(); }
insert_item(item);
count = count + 1;
if (count == 1) {
wakeup(consumer);
while (TRUE) {
if (count == 0) {
sleep(); }
int item = remove_item();
count = count - 1;
if (count == N - 1) {
wakeup(producer);
process_item(item);
Producer
Consumer

19. count 3 N 4 buffer ■ ■ ■ ■ ■ while (TRUE) { int item = produce_item();
if (count == N) {
sleep(); }
insert_item(item);
count = count + 1;
if (count == 1) {
wakeup(consumer);
while (TRUE) {
if (count == 0) {
sleep(); }
int item = remove_item();
count = count - 1;
if (count == N - 1) {
wakeup(producer);
process_item(item);
Producer
Consumer

20. count 3 N 4 buffer ■ ■ ■ ■ while (TRUE) { int item = produce_item();
if (count == N) {
sleep(); }
insert_item(item);
count = count + 1;
if (count == 1) {
wakeup(consumer);
while (TRUE) {
if (count == 0) {
sleep(); }
int item = remove_item();
count = count - 1;
if (count == N - 1) {
wakeup(producer);
process_item(item);
Producer
Consumer

21. Similarly…

22. count N 4 buffer while (TRUE) { int item = produce_item();N 4
buffer
while (TRUE) {
int item = produce_item();
if (count == N) {
sleep(); }
insert_item(item);
count = count + 1;
if (count == 1) {
wakeup(consumer);
while (TRUE) {
if (count == 0) {
sleep(); }
int item = remove_item();
count = count - 1;
if (count == N - 1) {
wakeup(producer);
process_item(item);
Producer
Consumer