进程与线程区别

#!/usr/bin/env python # encoding: utf-8 ?# Date: 2018/6/18# 1、开进程的开销远大于开线程的# import time# from threading import Thread# from multiprocessing import Process### def task(name):#???? print(‘%s is running ‘ % name)#???? time.sleep(2)#???? print(‘%s is done‘ % name)### if __name__ == ‘__main__‘:#???? # t1 = Thread(target=task,args=(‘线程1‘,))#???? # t1.start()#???? p1 = Process(target=task,))#???? p1.start()#???? print(‘主线程‘)# 2、同一个进程内的线程共享该进程的地址空间# from threading import Thread# from multiprocessing import Process# n = 100### def task():#???? global n#???? n = 0### if __name__ == ‘__main__‘:#???? t1 = Thread(target=task,)#???? t1.start()#???? t1.join()? # 主 0#???? # p1 = Process(target=task,)#???? # p1.start()#???? # p1.join()#???? print(‘主‘,n)? # 主 100# 3、瞅一眼pid# from multiprocessing import Process,current_process# import os### def task():#???? # print(current_process().pid)#???? print(‘子进程pid：%s? 父进程pid: %s‘ % (os.getpid(),os.getppid()))### if __name__ == ‘__main__‘:#???? p1 = Process(target=task,)#???? p1.start()#???? # print(‘主‘,current_process().pid)#???? print(‘主‘,os.getpid())? # 作用同上一行代码from threading import Threadimport osdef task():??? print(‘子线程pid：%s ‘ % (os.getpid()))? # 子线程pid：37352if __name__ == ‘__main__‘:??? p1 = Thread(target=task,)??? p1.start()??? print(‘主‘,os.getpid())? # 主 37352