并发编程-process对象的其他属性方法

Posted 2021-02-10 hexiaorui123

join方法：

 # join方法

from multiprocessing import Process
import time,os

def task():
    print(‘%s is running,parent id is <%s>‘ %(os.getpid(),os.getppid()))
    time.sleep(3)
    print(‘%s is done,parent id is <%s>‘%(os.getpid(),os.getppid()))

if __name__ == ‘__main__‘:
    p = Process(target=task)
    p.start()

    p.join()  # 主进程在等
    print(‘主‘,os.getpid(),os.getppid())
    print(p.pid)  # 获取p 的pid


并行运行时间为 等最长的那个进程执行完的时间
from multiprocessing import Process
import time,os

def task(name,n):
    print(‘%s is running‘ %name)
    time.sleep(n)

if __name__ == ‘__main__‘:
    start = time.time()
    p1=Process(target=task,args=(‘子进程1‘,5))
    p2=Process(target=task,args=(‘子进程2‘,3))
    p3=Process(target=task,args=(‘子进程3‘,2))
    p_l=[p1,p2,p3]

    # p1.start()  #  start 是发送信号
    # p2.start()
    # p3.start()
    for p in p_l:
        p.start()

    # p1.join()  # join 是等子进程运行完后，运行主进程。并发是等最长的时间的
    # p2.join()
    # p3.join()

    for p in p_l:
        p.join()
    print(‘主‘,(time.time()-start))  # 此为并发执行，执行时间为最长的那个



并行改为串行：时间为单个相加之和
from multiprocessing import Process
import time,os

def task(name,n):
    print(‘%s is running‘ %name)
    time.sleep(n)

if __name__ == ‘__main__‘:
    start=time.time()
    p1=Process(target=task,args=(‘子进程1‘,5))
    p2=Process(target=task,args=(‘子进程2‘,3))
    p3=Process(target=task,args=(‘子进程3‘,2))

    p1.start() #p1启动，p2,p3压根没启动
    p1.join()
    p2.start()
    p2.join()
    p3.start()
    p3.join()
    print(‘主‘,(time.time()-start))  # 此为单个的运行，时间为各个的加和，为10秒多




# 其他属性:is_alive
from multiprocessing import Process
import time,os

def task():
    print(‘%s is running,parent id is <%s>‘ %(os.getpid(),os.getppid()))
    time.sleep(3)
    print(‘%s is done,parent id is <%s>‘ %(os.getpid(),os.getppid()))

if __name__ == ‘__main__‘:
    p = Process(target=task,)
    p.start()
    print(p.is_alive())
    p.join()
    print(‘主‘,os.getpid(),os.getppid())
    print(p.pid)


#了解 :
from multiprocessing import Process
import time,os

def task():
    print(‘%s is running,parent is <%s>‘ %(os.getpid(),os.getppid()))
    time.sleep(3)
    print(‘%s is done,parent is <%s>‘ %(os.getpid(),os.getppid()))

if __name__ == ‘__main__‘:
    p = Process(target=task,name=‘sub-Process‘)
    p.start()
    p.terminate()  # 给操作系统发送终止信号
    print(p.is_alive())
    print(‘主‘)
    print(p.name)