为什么 ProcessPoolExecutor 串行工作？

Question

from concurrent.futures import ProcessPoolExecutor
import os
import time

def parInnerLoop(item):
    print(f'Processing {os.getpid()} started on {item}')
    time.sleep(3)
    print(f'Processing {os.getpid()} done on {item}')

def main():
    executor = ProcessPoolExecutor(max_workers=4)

    for itemNo in range(10):
        executor.submit(parInnerLoop(itemNo))

if __name__ == '__main__':
    main()

我想要实现的是并行 for 循环，类似于 MatLab，例如：

parfor itemNo = 0:9
    parInnerLoop(itemNo);
end

我得到的结果：所有 os.getpid 都相同，并且执行顺序发生。有帮助吗？

Windows, VSCodium/VSCode, Python 3.7.3

Answer 1

如@Klaus 所述，需要从 executor.submit(parInnerLoop(itemNo)) 更改为 executor.submit(parInnerLoop, itemNo)。

为什么 ProcessPoolExecutor 串行工作？

Why ProcessPoolExecutor working serially?

python

parallel-processing

concurrent.futures