python - 進程池 multiprocessing.Pool的簡單使用

import multiprocessing
import time
from queue import Queue

qurl = Queue()


def func(msg):
    print("msg:", msg)
    time.sleep(3)
    print("end")


def make_data():
    for i in range(10):
        qurl.put(i)
    print('------ qurl.qsize() = ', qurl.qsize())


def custom():
    pool = multiprocessing.Pool(processes=5)
    while not qurl.empty():
        data = qurl.get()
        print('--- data = ', data)
        pool.apply_async(func, (data,))  # 維持執行的進程總數爲processes，當一個進程執行完畢後會添加新的進程進去
    pool.close()
    pool.join()  # 調用join之前，先調用close函數，否則會出錯。執行完close後不會有新的進程加入到pool,join函數等待所有子進程結束


if __name__ == "__main__":
    start_time = time.time()
    make_data()
    print('make_data_end')
    custom()
    print('all task consum time = ', time.time() - start_time)