Python的进程及进程池详解

import multiprocessing
import os
import time
def work(name):
    print("子进程work正在运行......")
    time.sleep(0.5)
    print(name)
    # 获取进程的名称
    print("子进程name", multiprocessing.current_process())
    # 获取进程的pid
    print("子进程pid", multiprocessing.current_process().pid, os.getpid())
    # 获取父进程的pid
    print("父进程pid", os.getppid())
    print("子进程运行结束......")
if __name__ == '__main__':
    print("主进程启动")
    # 获取进程的名称
    print("主进程name", multiprocessing.current_process())
    # 获取进程的pid
    print("主进程pid", multiprocessing.current_process().pid, os.getpid())
    # 创建进程
    p = multiprocessing.Process(group=None, target=work, args=("tigeriaf", ))
    # 启动进程
    p.start()
    print("主进程结束")

import multiprocessing
import os
import time
def work(name):
    print("子进程work正在运行......")
    time.sleep(0.5)
    print(name)
    # 获取进程的名称
    print("子进程name", multiprocessing.current_process())
    # 获取进程的pid
    print("子进程pid", multiprocessing.current_process().pid, os.getpid())
    # 获取父进程的pid
    print("父进程pid", os.getppid())
    print("子进程运行结束......")
if __name__ == '__main__':
    print("主进程启动")
    # 获取进程的名称
    print("主进程name", multiprocessing.current_process())
    # 获取进程的pid
    print("主进程pid", multiprocessing.current_process().pid, os.getpid())
    # 创建进程
    p = multiprocessing.Process(group=None, target=work, args=("tigeriaf", ))
    # 启动进程
    p.start()
    p.join()
    print("主进程结束")

import multiprocessing
# 定义全局变量
num = 99
def work1():
    print("work1正在运行......")
    global num   # 在函数内部声明使⽤全局变量num
    num = num + 1  # 对num值进⾏+1
    print("work1 num = {}".format(num))
def work2():
    print("work2正在运行......")
    print("work2 num = {}".format(num))
if __name__ == '__main__':
    # 创建进程p1
    p1 = multiprocessing.Process(group=None, target=work1)
    # 启动进程p1
    p1.start()
    # 创建进程p2
    p2 = multiprocessing.Process(group=None, target=work2)
    # 启动进程p2
    p2.start()

import multiprocessing
import time
def work1():
    print("work1正在运行......")
    time.sleep(4)
    print("work1运行完毕")
def work2():
    print("work2正在运行......")
    time.sleep(10)
    print("work2运行完毕")
if __name__ == '__main__':
    # 创建进程p1
    p1 = multiprocessing.Process(group=None, target=work1)
    # 启动进程p1
    p1.start()
    # 创建进程p2
    p2 = multiprocessing.Process(group=None, target=work2)
    # 设置p2守护主进程
    # 第⼀种⽅式
    # p2.daemon = True  在start()之前设置，不然会抛异常
    # 启动进程p2
    p2.start()
    time.sleep(2)
    print("主进程运行完毕！")
    # 第⼆种⽅式 
    p2.terminate()

from multiprocessing import Pool
import time
def work(i):
    print("work'{}'执行中......".format(i), multiprocessing.current_process().name, multiprocessing.current_process().pid)
    time.sleep(2)
    print("work'{}'执行完毕......".format(i))
if __name__ == '__main__':
    # 创建进程池
    # Pool(3) 表示创建容量为3个进程的进程池
    pool = Pool(3)
    for i in range(10):
        # 利⽤进程池同步执⾏work任务，进程池中的进程会等待上⼀个进程执行完任务后才能执⾏下⼀个进程
        # pool.apply(work, (i, ))
        # 使⽤异步⽅式执⾏work任务
        pool.apply_async(work, (i, ))
    # 进程池关闭之后不再接受新的请求
    pool.close()
    # 等待po中所有子进程结束，必须放在close()后面, 如果使⽤异步⽅式执⾏work任务，主线程不再等待⼦线程执⾏完毕再退出！
    pool.join()