python manager.dict()锁定的工作方式: [英] How python manager.dict() locking works:

问题描述

A managers.dict()允许跨进程共享字典并执行线程安全操作. 在我的情况下，每个协调程序进程都使用m元素创建共享的dict，而n工作进程则对单个dict键进行读写操作.

A managers.dict() allow to share a dictionary across process and perform thread-safe operation. In my case each a coordinator process create the shared dict with m elements and n worker processes read and write to/from a single dict key.

managers.dict()的dict锁或m的锁是否只有一个，而其中的每个键都有一个?

Do managers.dict() have one single lock for the dict or m locks, one for every key in it?

当共享对象不需要彼此通信时，是否有其他方法可以将共享m元素共享给n共享对象?

Is there an alternative way to share m elements to n workers, other than a shared dict, when the workers do not have to communicate with each other?

相关 python-manager-dict-is-与常规字典相比非常慢

推荐答案

经过一番尝试，我可以说每个管理人员命令只有一个锁. 这是证明它的代码:

After some tries I can say there is only one lock per managers dict. Here is the code that proves it:

import time
import multiprocessing as mp


def process_f(key, shared_dict):
        values = [i for i in range(64 * 1024 * 1024)]
        print "Writing {}...".format(key)
        a = time.time()
        shared_dict[key] = values
        b = time.time()
        print "released {} in {}ms".format(key, (b-a)*1000)


def main():
    process_manager = mp.Manager()
    n = 5
    keys = [i for i in range(n)]
    shared_dict = process_manager.dict({i: i * i for i in keys})

    pool = mp.Pool(processes=n)

    for i in range(n):
        pool.apply_async(process_f, (keys[i], shared_dict))
    time.sleep(20)


if __name__ == '__main__':
    main()

输出:

Writing 4...
Writing 3...
Writing 1...
Writing 2...
Writing 0...
released 4 in 3542.7968502ms
released 0 in 4416.22900963ms
released 1 in 6247.48706818ms
released 2 in 7926.97191238ms
released 3 in 9973.71196747ms

Process finished with exit code 0

写作时间的增加表明正在等待.

The increasing time for writing show the waiting which is happening.

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