python3多进程和进程池

Posted 2021-01-22 fengzi7314

#一个程序运行起来之后，代码+用到的资源称之为进程，它是操作系统分配资源的基本单位，不仅可以通过线程完成多任务，进程也是可以的
#进程之间是相互独立的
#cpu密集的时候适合用多进程

#多进程并发
import multiprocessing
from multiprocessing import Pool
import time
def test1():
    for i in range(10):
        time.sleep(1)
        print(‘test‘, i)

def test2():
    for i in range(10):
        time.sleep(1)
        print(‘test‘, i)

if __name__ == ‘__main__‘:
    p1 = multiprocessing.Process(target=test1)
    p2 = multiprocessing.Process(target=test2)
    p1.start()
    p2.start()

#进程之间不共享
import multiprocessing
from multiprocessing import Pool
import time
import threading
g_num = 0
def edit():
    global g_num
    for i in range(10):
        g_num += 1

def reader():
    print(g_num)


if __name__ == ‘__main__‘:
    # t1 = threading.Thread(target=edit)
    # t2 = threading.Thread(target=reader)
    # t1.start()
    # t2.start()
    p1 = multiprocessing.Process(target=edit)
    p2 = multiprocessing.Process(target=reader())
    p1.start()
    p1.join()
    p2.start()

#进程池实现并发
import multiprocessing
from multiprocessing import Pool
import time
import threading
g_num = 0
def test1():
    for i in range(10):
        time.sleep(1)
        print(‘test1‘, i)

def test2():
    for i in range(10):
        time.sleep(1)
        print(‘test2‘, i)


if __name__ == ‘__main__‘:
    # t1 = threading.Thread(target=edit)
    # t2 = threading.Thread(target=reader)
    # t1.start()
    # t2.start()
    # p1 = multiprocessing.Process(target=edit)
    # p2 = multiprocessing.Process(target=reader())
    # p1.start()
    # p1.join()
    # p2.start()
    pool = Pool()
    pool.apply_async(test1)
    pool.apply_async(test2)
    pool.close()
    pool.join()