![producer: consumer:
while (true) while (true)
{ {
/* produce item v */ while (in <= out)
b[in] = v; /* do nothing */;
in++
} w = b[out];
out = (out + 1);
/* consume item w */
}
19](https://image.slidesharecdn.com/mutualexclusionandsynchronization-120707161254-phpapp02/85/Mutual-exclusion-and-synchronization-19-320.jpg)
Mutual exclusion and synchronization
- 4. Wikipedia
- 5. We have features for every step of the way
- 6. Design, organize, and collaborate
- 7. Semaphore o o
- 8. Stylize, edit, and animate your media
- 9. Broadcast and compress for seamless delivery
- 10. semSignal semWait semWait wait
- 13. semaphore s=1; P0 () P1 () { { semWait (s); semWait (s); <CS> <CS> semSignal (s); semSignal (s); } }
- 15. • n • • 15
- 16. semaphore s=1; P0 () P1 () { { semWaitB (s); semWaitB (s); <CS> <CS> semSignalB (s); semSignalB (s); } } 16
- 17. Producer and Consumer • • – • – 17
- 18. • • – – • – 18
- 19. producer: consumer: while (true) while (true) { { /* produce item v */ while (in <= out) b[in] = v; /* do nothing */; in++ } w = b[out]; out = (out + 1); /* consume item w */ } 19
- 20. n delay (n=1) 20
- 21. 21
- 22. 22
- 23. n wait 23
- 24. y x • z x Processes z y W(z) z n>=0 y x W(y) z n>=0 y n>=1 x W(x) z y x z n>=0 y x <CS> S(x) (n>=0) z z • S(y) y z S(z) x y y .. x 24
- 25. S a P3 P2 P1 • S semWait W semSignal P1 P2 P3 P2 P1 P3 P2 P2 P3 P1 W(a) W(a) S(a) W(a) S(a) S(a) W(a) W(a) S(a) W(a) • P3 P2 P1 • P2 P3 P1 • P1 P3 P2 • 25
- 26. P1 P2 P3 P2 P1 P3 P2 P2 P3 P1 W(a) W(a) S(a) W(a) S(a) S(a) W(a) W(a) S(a) W(a) a 0 -1 0 -1 0 1 0 -1 0 -1 P2 P2 P2 P1 26
- 27. 27
- 28. 28
- 29. n n • n • • • – 29
- 30. • 30
- 31. 31
- 32. Monitor • • • – – – • 32
- 33. 33
- 34. cwait(c) • c csignal (c) • cwait wait/signal • 34
- 35. 35
- 36. • • • 36
- 37. • 37
- 38. mayconsume • capacity • mayproduce mayproduce • 38
Editor's Notes
- #2: Ahmadniroomand