我是一个对Python比较新的人。我一直在学习和研究多进程模块,但在使用锁时遇到了困难。
这里是测试代码:
import multiprocessing
from multiprocessing import Pool
class Param_Class():
#Initialisation.
def __init__(self):
self.counter = multiprocessing.Value('i',0)
self.lock = multiprocessing.Lock()
def inc_counter(self):
lk.acquire()
print('Locked {}'.format(multiprocessing.current_process().name))
self.counter.value+=1
lk.release()
print('Released {}'.format(multiprocessing.current_process().name))
param_class = Param_Class()
def init(lock):
global lk
lk = lock
def target():
param_class.inc_counter()
code = 0
return code
def handler(i):
if i<50:
code = target()
print(param_class.counter.value)
if __name__ == '__main__':
p = Pool(processes=2,initializer=init, initargs=(param_class.lock,))
p.map_async(handler,range(50))
p.close()
p.join()
我希望的是每个进程在执行时都被锁定,这样我的计数器应该在任何一个进程被执行时递增。然而,进程之间没有互锁,第二个进程正在使用计数器的副本。
以下是输出:
Locked SpawnPoolWorker-1
Released SpawnPoolWorker-1
1
Locked SpawnPoolWorker-1
Released SpawnPoolWorker-1
Locked SpawnPoolWorker-2
2
Released SpawnPoolWorker-2
1
Locked SpawnPoolWorker-1
Locked SpawnPoolWorker-2
Released SpawnPoolWorker-1
Released SpawnPoolWorker-2
3
2
Locked SpawnPoolWorker-1
Released SpawnPoolWorker-1
Locked SpawnPoolWorker-2
4
Released SpawnPoolWorker-2
Locked SpawnPoolWorker-1
3
Released SpawnPoolWorker-1
Locked SpawnPoolWorker-2
5
Released SpawnPoolWorker-2
Locked SpawnPoolWorker-1
4
Released SpawnPoolWorker-1
Locked SpawnPoolWorker-2
6
Released SpawnPoolWorker-2
Locked SpawnPoolWorker-1
5
Released SpawnPoolWorker-1
Locked SpawnPoolWorker-2
7
Released SpawnPoolWorker-2
Locked SpawnPoolWorker-1
6
Released SpawnPoolWorker-1
Locked SpawnPoolWorker-2
8
Released SpawnPoolWorker-2
Locked SpawnPoolWorker-1
7
Released SpawnPoolWorker-1
Locked SpawnPoolWorker-2
9
Released SpawnPoolWorker-2
Locked SpawnPoolWorker-1
8
Released SpawnPoolWorker-1
Locked SpawnPoolWorker-2
10
Released SpawnPoolWorker-2
Locked SpawnPoolWorker-1
9
Released SpawnPoolWorker-1
Locked SpawnPoolWorker-2
11
Released SpawnPoolWorker-2
10
Locked SpawnPoolWorker-1
Locked SpawnPoolWorker-2
Released SpawnPoolWorker-1
Released SpawnPoolWorker-2
12
11
Locked SpawnPoolWorker-1
Released SpawnPoolWorker-1
Locked SpawnPoolWorker-2
13
Released SpawnPoolWorker-2
12
Locked SpawnPoolWorker-1
Released SpawnPoolWorker-1
Locked SpawnPoolWorker-2
14
Released SpawnPoolWorker-2
13
Locked SpawnPoolWorker-1
Released SpawnPoolWorker-1
Locked SpawnPoolWorker-2
15
Released SpawnPoolWorker-2
Locked SpawnPoolWorker-1
14
Released SpawnPoolWorker-1
Locked SpawnPoolWorker-2
16
Released SpawnPoolWorker-2
Locked SpawnPoolWorker-1
15
Released SpawnPoolWorker-1
Locked SpawnPoolWorker-2
17
Released SpawnPoolWorker-2
Locked SpawnPoolWorker-1
16
Released SpawnPoolWorker-1
Locked SpawnPoolWorker-2
18
Released SpawnPoolWorker-2
Locked SpawnPoolWorker-1
17
Released SpawnPoolWorker-1
Locked SpawnPoolWorker-2
19
Released SpawnPoolWorker-2
Locked SpawnPoolWorker-1
18
Released SpawnPoolWorker-1
Locked SpawnPoolWorker-2
20
Released SpawnPoolWorker-2
Locked SpawnPoolWorker-1
19
Released SpawnPoolWorker-1
Locked SpawnPoolWorker-2
21
Released SpawnPoolWorker-2
Locked SpawnPoolWorker-1
20
Released SpawnPoolWorker-1
Locked SpawnPoolWorker-2
22
Released SpawnPoolWorker-2
Locked SpawnPoolWorker-1
21
Released SpawnPoolWorker-1
Locked SpawnPoolWorker-2
23
Released SpawnPoolWorker-2
Locked SpawnPoolWorker-1
22
Released SpawnPoolWorker-1
24
Locked SpawnPoolWorker-1
Released SpawnPoolWorker-1
25
Locked SpawnPoolWorker-1
Released SpawnPoolWorker-1
26
Locked SpawnPoolWorker-1
Released SpawnPoolWorker-1
27
Locked SpawnPoolWorker-1
Released SpawnPoolWorker-1
28
期望的输出应该类似于这样:
Locked SpawnPoolWorker-1
1
Released SpawnPoolWorker-1
Locked SpawnPoolWorker-2
2
Released SpawnPoolWorker-2
Locked SpawnPoolWorker-1
3
Released SpawnPoolWorker-1
.
.
.
.
.
.
.
Locked SpawnPoolWorker-2
50
Released SpawnPoolWorker-2
我参考了 这个页面 来了解如何初始化锁并继承它。我无法理解我哪里出了错。是锁、
multiprocessing.Pool
调用或使用类实例或目标函数本身的问题。请详细说明,并支持一些理论。我想学习这个,而不仅仅是解决它。注意,在获得的输出中,从值24到28按预期工作,进程2停止工作。需要对此进行澄清。
附:我想避免使用管理器,因为像链接中提到的那样,管理器很重量级。另外,我不想消除部分并发执行,因为我将使用其他不需要锁定的变量,并且希望该模块保持快速和pythonic。