Question

因此，我开始尝试使用Python的多处理库。我的目标是加快一个慢速函数的运行速度，该函数将字符串与其他字符串的大型数据库进行比较，并返回最相似的匹配项。为此，我尝试编写一个函数，使用共享变量捕获结果，以将该任务拆分为不同的Process对象，并使它们运行。

cores = cpu_count() # Number of cores in this computer, i.e. 4
sublistList = chunks(tasks,cores) # Split tasks into subprocessing arrays of evenly-sized chunks, the number of chunks equal to how many cores we have to process them

# Create a multiprocessing function, since this is a large function that will take time and splitting it across cores will ease the load
if __name__ == '__main__':

    freeze_support() # Make sure multiple applications don't spawn, this is necessary for Windows

    jobs = [] # Array of processes
    manager = Manager() # Create a manager
    returns = manager.list() # Shared list variable we use to get return results

    for i in range(0,cores): # For number of cores...

        p = Process(target=workerFunction,args=(w,sublistList[i],returns))
        jobs.append(p) # Add to array of processes to run
        p.start()

    for p in jobs:

        p.join()

但是，当我运行此代码时，它将创建一个新的应用程序窗口，然后无限期挂起，这完全是奇怪的行为，根本不是我想要的。是什么在我的代码中引起这种情况？我的工作人员功能是否在默默地崩溃并且没有提醒我？我查看了各种其他答案，但是没有一个建议的答案似乎可以解决此问题。

（如果与问题相关，我是一名入门级软件工程师，具有几年使用其他语言的编程经验，但是对于Python来说还比较陌生。这是我的一个小型独立游戏项目。）

Answer 1

（目前）还没有答案，但我将其发布给您以展示可运行 Minimal, Complete, and Verifiable Example的示例。

代码基于您的问题中的当前内容，以及使它可运行所需的所有其他内容。毫不奇怪，由于所有这些只是猜测，它不会重现您说的问题，但这很可能是由于我的一个或多个猜测在某些重要方面有所不同...这就是为什么您真的应该提供所有代码的原因。

一个观察结果：最后的p.join()调用将使主进程等待每个子进程完成。这将导致在等待每个主进程时主进程似乎“挂起”。

from multiprocessing import *
from time import sleep

tasks = None

def chunks(tasks, cores):
    return [[i for _ in range(8)] for i in range(cores)]

def workerFunction(w, sublist, returns):
    print('starting workerFunction:', w)
    result = [value+100 for value in sublist]
    returns.append(result)
    sleep(3)
    print('exiting workerFunction:', w)

if __name__ == '__main__':

    # Only do in main process.
    freeze_support()
    cores = cpu_count()
    sublistList = chunks(tasks, cores)
    manager = Manager()
    returns = manager.list()
    jobs = []

    for i in range(cores):
        w = i
        p = Process(target=workerFunction, args=(w, sublistList[i], returns))
        jobs.append(p)
        p.start()

    for i, p in enumerate(jobs, 1):
        print('joining job[{}]'.format(i))
        p.join()

    # Display results.
    for sublist in returns:
        print(sublist)

    print('done')

输出：

joining job[1]
starting workerFunction: 2
starting workerFunction: 1
starting workerFunction: 0
starting workerFunction: 5
starting workerFunction: 7
starting workerFunction: 3
starting workerFunction: 4
starting workerFunction: 6
exiting workerFunction: 2
exiting workerFunction: 0
exiting workerFunction: 1
joining job[2]
exiting workerFunction: 5
joining job[3]
joining job[4]
exiting workerFunction: 7
exiting workerFunction: 3
exiting workerFunction: 4
joining job[5]
exiting workerFunction: 6
joining job[6]
joining job[7]
joining job[8]
[102, 102, 102, 102, 102, 102, 102, 102]
[101, 101, 101, 101, 101, 101, 101, 101]
[100, 100, 100, 100, 100, 100, 100, 100]
[105, 105, 105, 105, 105, 105, 105, 105]
[107, 107, 107, 107, 107, 107, 107, 107]
[103, 103, 103, 103, 103, 103, 103, 103]
[104, 104, 104, 104, 104, 104, 104, 104]
[106, 106, 106, 106, 106, 106, 106, 106]
done
Press any key to continue . . .

多处理进程挂起

1 个答案: