Benjamin Peterson | e711caf | 2008-06-11 16:44:04 +0000 | [diff] [blame] | 1 | import time |
| 2 | import random |
| 3 | |
| 4 | from multiprocessing import Process, Queue, current_process, freeze_support |
| 5 | |
| 6 | # |
| 7 | # Function run by worker processes |
| 8 | # |
| 9 | |
| 10 | def worker(input, output): |
| 11 | for func, args in iter(input.get, 'STOP'): |
| 12 | result = calculate(func, args) |
| 13 | output.put(result) |
| 14 | |
| 15 | # |
| 16 | # Function used to calculate result |
| 17 | # |
| 18 | |
| 19 | def calculate(func, args): |
| 20 | result = func(*args) |
| 21 | return '%s says that %s%s = %s' % \ |
Benjamin Peterson | 58ea9fe | 2008-08-19 19:17:39 +0000 | [diff] [blame] | 22 | (current_process().name, func.__name__, args, result) |
Benjamin Peterson | e711caf | 2008-06-11 16:44:04 +0000 | [diff] [blame] | 23 | |
| 24 | # |
| 25 | # Functions referenced by tasks |
| 26 | # |
| 27 | |
| 28 | def mul(a, b): |
| 29 | time.sleep(0.5*random.random()) |
| 30 | return a * b |
| 31 | |
| 32 | def plus(a, b): |
| 33 | time.sleep(0.5*random.random()) |
| 34 | return a + b |
| 35 | |
| 36 | # |
| 37 | # |
| 38 | # |
| 39 | |
| 40 | def test(): |
| 41 | NUMBER_OF_PROCESSES = 4 |
| 42 | TASKS1 = [(mul, (i, 7)) for i in range(20)] |
| 43 | TASKS2 = [(plus, (i, 8)) for i in range(10)] |
| 44 | |
| 45 | # Create queues |
| 46 | task_queue = Queue() |
| 47 | done_queue = Queue() |
| 48 | |
| 49 | # Submit tasks |
| 50 | for task in TASKS1: |
| 51 | task_queue.put(task) |
| 52 | |
| 53 | # Start worker processes |
| 54 | for i in range(NUMBER_OF_PROCESSES): |
| 55 | Process(target=worker, args=(task_queue, done_queue)).start() |
| 56 | |
| 57 | # Get and print results |
Christian Heimes | aae1b70 | 2008-11-28 11:23:26 +0000 | [diff] [blame] | 58 | print('Unordered results:') |
Benjamin Peterson | e711caf | 2008-06-11 16:44:04 +0000 | [diff] [blame] | 59 | for i in range(len(TASKS1)): |
Christian Heimes | aae1b70 | 2008-11-28 11:23:26 +0000 | [diff] [blame] | 60 | print('\t', done_queue.get()) |
Benjamin Peterson | e711caf | 2008-06-11 16:44:04 +0000 | [diff] [blame] | 61 | |
| 62 | # Add more tasks using `put()` |
| 63 | for task in TASKS2: |
| 64 | task_queue.put(task) |
| 65 | |
| 66 | # Get and print some more results |
| 67 | for i in range(len(TASKS2)): |
Christian Heimes | aae1b70 | 2008-11-28 11:23:26 +0000 | [diff] [blame] | 68 | print('\t', done_queue.get()) |
Benjamin Peterson | e711caf | 2008-06-11 16:44:04 +0000 | [diff] [blame] | 69 | |
| 70 | # Tell child processes to stop |
| 71 | for i in range(NUMBER_OF_PROCESSES): |
| 72 | task_queue.put('STOP') |
| 73 | |
| 74 | |
| 75 | if __name__ == '__main__': |
| 76 | freeze_support() |
| 77 | test() |