目录
- python并发编程02/多进程
- 1.进程创建的两种方式
- 1.1开启进程的第一种方式
- 1.2开启进程的第二种方式
- 1.3简单应用
- 2.进程pid
- 2.1命令行获取所有的进程的pid tasklist
- 2.2代码级别如何获取一个进程的pid
- 2.3获取父进程(主进程)的pid
- 3.验证进程之间的空间隔离
- 4.进程对象join方法
- 5.进程对象其他属性
- 6.守护进程
- 1.进程创建的两种方式
python并发编程02/多进程
1.进程创建的两种方式
1.1开启进程的第一种方式
from multiProcessing import Process
import time
def task(name):
print(f'{name} is running')
time.sleep(2)
print(f'{name} is gone')
if __name__ == '__main__':
#在window环境下,开启进程必须__name=='__main__'下面
p = Process(target=task,args=('太阳',)) #创建一个进程对象
p.start() #只是向操作系统发出一个开辟子进程的信号,然后就执行下一行了
#这个信号操作系统接收到之后,会从内存中开辟子进程空间,然后再将主进程所有数据copy加载到子进程,然后再调用CPU去执行.
#开辟子进程开销是很大的
print('==主开始')
time.sleep(3)
#所以永远会先执行主进程的代码1.2开启进程的第二种方式
# from multiprocessing import Process
# import time
#
# class MyProcess(Process):
#
# def __init__(self,name):
# super().__init__()
# self.name = name
#
# def run1(self):
# print(f'{self.name} is running')
# time.sleep(2)
# print(f'{self.name} is gone')
#
#
# if __name__ == '__main__':
# p = MyProcess('太阳')
# p.start()
# print('===主')1.3简单应用
# from multiprocessing import Process
# import time
#
# def task(name):
# print(f'{name} is running')
# time.sleep(1)
# print(f'{name} is gone')
#
# def task1(name):
# print(f'{name} is running')
# time.sleep(2)
# print(f'{name} is gone')
#
# def task2(name):
# print(f'{name} is running')
# time.sleep(3)
# print(f'{name} is gone')
#
#
# if __name__ == '__main__':
# # 在windows环境下, 开启进程必须在 __name__ == '__main__' 下面
# # 一个进程串行的执行三个任务
# start_time = time.time()
# task('太阳')
# task1('月亮')
# task2('星星')
# print(f'结束时间{time.time() - start_time}')
# 三个进程 并发或者并行的执行三个任务
# start_time = time.time()
# p1 = Process(target=task, args=('太阳',)) # 创建一个进程对象
# p2 = Process(target=task1, args=('月亮',))# 创建一个进程对象
# p1.start()
# p2.start()
# task2('星星')
# print(f'结束时间{time.time()-start_time}')2.进程pid
2.1命令行获取所有的进程的pid tasklist
2.2代码级别如何获取一个进程的pid
import os
print(os.getpid())2.3获取父进程(主进程)的pid
import os
import time
print(f'子进程:{os.getpid()}')
print(f'主(父)进程:{os.getppid(())}')3.验证进程之间的空间隔离
#from multiprocessing import Process
#import os
#import time
# name = 'dabai'
#
# def task():
# global name
# name = 'ergou'
# print(f'子进程{name}')
#
#
# if __name__ == '__main__':
# p = Process(target=task) # 创建一个进程对象
# p.start()
# # print('==主开始')
# time.sleep(3)
# print(f'主:{name}')4.进程对象join方法
join让主进程等待子进程结束后,再执行主进程
# from multiprocessing import Process
# import time
#
# def task(name):
# print(f'{name} is running')
# time.sleep(2)
# print(f'{name} is gone')
#
#
#
# if __name__ == '__main__':
#
# p = Process(target=task,args=('太阳',)) # 创建一个进程对象
# p.start()
# p.join()
# print('==主开始')
多个子进程使用join
# from multiprocessing import Process
# import time
#
# def task(name,sec):
# print(f'{name}is running')
# time.sleep(sec)
# print(f'{name} is gone')
#
#
# if __name__ == '__main__':
# start_time = time.time()
# p1 = Process(target=task,args=('太阳',1))
# p2 = Process(target=task,args=('月亮',2))
# p3 = Process(target=task,args=('星星',3))
# p1.start()
# p2.start()
# p3.start()
# print(f'==主{time.time()-start_time}') # 0.02 这只是主进程结束的时间,与其他进程毫无关系
验证 1
# from multiprocessing import Process
# import time
#
# def task(name,sec):
# print(f'{name}is running')
# time.sleep(sec)
# print(f'{name} is gone')
#
#
# if __name__ == '__main__':
# start_time = time.time()
# p1 = Process(target=task,args=('太阳',1))
# p2 = Process(target=task,args=('月亮',2))
# p3 = Process(target=task,args=('星星',3))
#
# p1.start()
# p2.start()
# p3.start()
# # join 只针对主进程,如果join下面多次join 他是不阻塞的.
# p1.join()
# p2.join()
# p3.join()
#
# print(f'==主{time.time()-start_time}')
验证 2
# from multiprocessing import Process
# import time
#
# def task(name,sec):
# print(f'{name}is running')
# time.sleep(sec)
# print(f'{name} is gone')
#
#
# if __name__ == '__main__':
# start_time = time.time()
# p1 = Process(target=task,args=('太阳',3))
# p2 = Process(target=task,args=('月亮',2))
# p3 = Process(target=task,args=('星星',1))
#
# p1.start()
# p2.start()
# p3.start()
# # join就是阻塞
#
# p1.join() # 等2s
# print(f'==主1:{time.time()-start_time}')
# p2.join()
# print(f'===主2:{time.time()-start_time}')
# p3.join()
# print(f'==主3:{time.time()-start_time}') #
优化上面的方法
# from multiprocessing import Process
# import time
#
# def task(sec):
# print(f'is running')
# time.sleep(sec)
# print(f' is gone')
#
#
# if __name__ == '__main__':
# start_time = time.time()
# p1 = Process(target=task,args=(1,))
# p2 = Process(target=task,args=(2,))
# p3 = Process(target=task,args=(3,))
#
# p1.start()
# p2.start()
# p3.start()
# # join 只针对主进程,如果join下面多次join 他是不阻塞的.
# p1.join()
# p2.join()
# p3.join()
错误示范:
# for i in range(1,4):
# p = Process(target=task,args=(i,))
# p.start()
# p.join()
# '''
# p1 = Process(target=task,args=(1,))
# p1.start()
# p1.join()
# p2 = Process(target=task,args=(2,))
# p2.start()
# p2.join()
# p3 = Process(target=task,args=(3,))
# p3.start()
# p3.join()
#
# '''
正确示范:
# l1 = []
# for i in range(1, 4):
# p = Process(target=task,args=(i,))
# l1.append(p)
# p.start()
#
# for i in l1:
# i.join()
#
# print(f'==主{time.time()-start_time}')
join就是阻塞,主进程有join,主进程下面的代码一律不执行,直到进程执行完毕之后,在执行.5.进程对象其他属性
# from multiprocessing import Process
# import time
#
# def task(name):
# print(f'{name} is running')
# time.sleep(2)
# print(f'{name} is gone')
#
#
# if __name__ == '__main__':
# # 在windows环境下, 开启进程必须在 __name__ == '__main__' 下面
# # p = Process(target=task,args=('太阳',)) # 创建一个进程对象
# p = Process(target=task,args=('太阳',),name='月亮') # 创建一个进程对象
# p.start()
# # time.sleep(1)
# # p.terminate() # 杀死子进程 ***
# # p.join() # ***
# # time.sleep(0.5)
# # print(p.is_alive()) # ***
# # print(p.name)
# p.name = 'sb'
# print(p.name)
# print('==主开始')6.守护进程
# 古时候 太监守护这个皇帝,如果皇帝驾崩了,太监直接也就死了.
子进程守护着主进程,只要主进程结束,子进程就跟着结束
# from multiprocessing import Process
# import time
#
# def task(name):
# print(f'{name} is running')
# time.sleep(2)
# print(f'{name} is gone')
#
# if __name__ == '__main__':
# # 在windows环境下, 开启进程必须在 __name__ == '__main__' 下面
# p = Process(target=task,args=('太阳',)) # 创建一个进程对象
# p.daemon = True # 将p子进程设置成守护进程,只要主进程结束,守护进程马上结束.
# p.start()
# # p.daemon = True # 一定要在子进程开启之前设置
# time.sleep(1)
# print('===主')原文地址：https://www.cnblogs.com/liubing8/p/11386143.html
时间： 2024-08-08 17:21:25