多进程 ​

import os

pid = os.fork()
if pid == 0:
    print("I'm subprocess,my pid is %d and my ppid is %d" % (os.getpid(), os.getppid()))
else:
    print("I'm host process,my pid is %d" % os.getpid())

from multiprocessing import Process
import os
import time


def process_request(interval):
    print("subprocess's PID is %d and host process's PID is %d " % (os.getpid(), os.getppid()))
    time.sleep(interval)  # 模拟耗时操作


def main():
    pr = Process(target=process_request, args=(5,), name="pr")  # 创建子进程
    pr.start()  # 启动子进程
    print(pr.is_alive())  # 判断pr进程是否在运行
    pr.join()  # 等待pr执行完成后再执行下面代码
    print("%s process finished" % pr.name)


if __name__ == "__main__":
    main()

from multiprocessing import Process
import os
import time


class PRProcess(Process):
    def __init__(self, request):
        super().__init__()  # 务必执行父类初始化方法
        self.__request = request

    def run(self):  # 会被自动调用
        print("subprocess's PID is %d and host process's PID is %d " % (os.getpid(), os.getppid()))
        time.sleep(2)  # 模拟耗时操作
        print("%s processed" % self.__request)


def main():
    pr = PRProcess("request-0")
    pr.start()


if __name__ == "__main__":
    main()

from multiprocessing import Pool
import os
import time


def process_request(request):
    time.sleep(2)  # 模拟耗时操作
    print("%s processed by process %d" % (request, os.getpid()))


def main():
    pool = Pool(3)  # 创建进程池，并指定最大进程数
    for i in range(10):
        pool.apply_async(process_request, ("request-%d" % i,))  # 给进程池分派任务

    pool.close()  # 关闭进程池
    pool.join()  # 等待进程池中所有任务结束
    print("all done")


if __name__ == "__main__":
    main()

from multiprocessing import Pool, Manager
import os
import time
import random


def produce(queue):
    while True:
        product = random.randint(10, 20)
        print("process-%s produced product-%d\t%s" % (os.getpid(), product, time.ctime()))
        queue.put(product)  # 入队

        time.sleep(random.randint(1, 3))


def consume(queue):
    while True:
        if not queue.empty():
            print("process-%s consumed product-%d\t%s" % (os.getpid(), queue.get(), time.ctime()))  # 出队

        time.sleep(random.randint(1, 3))


def main():
    queue = Manager().Queue()  # 创建队列
    pool = Pool()  # 创建进程池
    for i in range(2):
        pool.apply_async(produce, (queue,))  # 创建2个生产者
    for i in range(3):
        pool.apply_async(consume, (queue,))  # 创建3个消费者

    pool.close()
    pool.join()


if __name__ == "__main__":
    main()