Question

这是我的Python代码。

#!/usr/bin/env python
import multiprocessing
import time

def worker(q):
    while True:
        data = q.get()
        print 'worker: got: %d' % data
        if data == -1:
            print 'worker: done'
            break

def master():
    q = multiprocessing.Queue()
    p = multiprocessing.Process(target=worker, args=(q,))
    p.start()

    for i in range(5):
        q.put(i)
        print 'master: put: %d' % i
        time.sleep(1)

    q.put(-1)
    p.join()

    print 'master: done'

master()
print 'exiting ...'

这是我在Debian 9 GNU / Linux系统上运行此代码时的输出。

$ python q.py
master: put: 0
worker: got: 0
master: put: 1
worker: got: 1
master: put: 2
worker: got: 2
master: put: 3
worker: got: 3
master: put: 4
worker: got: 4
worker: got: -1
worker: done
master: done
exiting ...

我试图找到一些证据表明主进程和工作进程正在通过传递队列中的数据进行通信套接字，消息队列或共享内存。但我似乎找不到任何东西支持它的证据。

$ ps -ef | grep python | grep -v grep; netstat -nopa | grep python; ipcs
lone      2914  9836  2 12:54 pts/1    00:00:00 python q.py
lone      2915  2914  0 12:54 pts/1    00:00:00 python q.py
(Not all processes could be identified, non-owned process info
 will not be shown, you would have to be root to see it all.)

------ Message Queues --------
key        msqid      owner      perms      used-bytes   messages

------ Shared Memory Segments --------
key        shmid      owner      perms      bytes      nattch     status
0x00000000 163840     lone       600        393216     2          dest
0x00000000 262145     lone       600        393216     2          dest
0x00000000 360450     lone       600        393216     2          dest
0x00000000 142344195  lone       600        524288     2          dest
0x00000000 101941252  lone       600        4194304    2          dest
0x00000000 950277     lone       600        524288     2          dest
0x00000000 118194183  lone       600        696320     2          dest
0x00000000 118292488  lone       600        4153344    2          dest
0x00000000 117899273  lone       600        4153344    2          dest
0x00000000 118226954  lone       600        696320     2          dest
0x00000000 123535371  lone       600        86016      2          dest
0x00000000 123338764  lone       600        1728512    2          dest
0x00000000 123240461  lone       600        1798144    2          dest
0x00000000 123568144  lone       600        86016      2          dest
0x00000000 137330705  lone       600        32768      2          dest
0x00000000 137232402  lone       600        81920      2          dest
0x00000000 29098003   lone       600        4194304    2          dest
0x00000000 137265172  lone       600        81920      2          dest
0x00000000 137297941  lone       600        151552     2          dest
0x00000000 35258391   lone       600        393216     2          dest
0x00000000 35291160   lone       600        12288      2          dest
0x00000000 35323929   lone       600        12288      2          dest
0x00000000 35356698   lone       600        393216     2          dest
0x00000000 35520539   lone       600        12288      2          dest
0x00000000 35422236   lone       600        393216     2          dest
0x00000000 35455005   lone       600        12288      2          dest

------ Semaphore Arrays --------
key        semid      owner      perms      nsems

如何将数据放入multiprocessing.Queue 主要流程到工作流程？
我可以运行哪些命令来查找用于将multiprocessing.Queue中的数据从主进程传输到工作进程的IPC机制的证据？

Answer 1

Python是开源的，你可以在这里清楚地看到实现：https://github.com/python/cpython/blob/master/Lib/multiprocessing/queues.py

它使用Pipe来实现：https://github.com/python/cpython/blob/master/Lib/multiprocessing/connection.py

使用os.pipe()，在此处实施：https://github.com/python/cpython/blob/master/Modules/posixmodule.c

使用pipe2()，在此处记录：http://man7.org/linux/man-pages/man2/pipe.2.html

什么IPC机制用于在多处理中共享数据。两个Python进程之间的值？

1 个答案: