进程vs线程

进程vs线程创建速度

from threading import Thread
from multiprocessing import Process
import time

def task(name):
    print(f'{name} is running')
    time.sleep(2)
    print(f'{name} is end')


if __name__ == '__main__':
    t = Thread(target=task,args=('子线程',))
    p = Process(target=task,args=('子进程',))
    # t.start()
    p.start()
    print('主')

开启子线程的打印效果:

• 子线程 is running

• 主子线程 is end

开启子进程打印效果:

• 主子进程 is running

• 子进程 is end

进程和线程的创建速度

• 开启子进程需要申请资源开辟空间
  • 慢
• 开启子线程只是告诉操作系统一个执行方案
  • 快

多线程vs多进程

计算密集型

from threading import Thread
from multiprocessing import Process
import time

# 计算密集型
# def work1():
#     res=0
#     for i in range(100000000): #1+8个0
#         res*=i
#
# if __name__ == '__main__':
#     t_list = []
#     start = time.time()
#     for i in range(4):
#         # t = Thread(target=work1)
#         t = Process(target=work1)
#         t_list.append(t)
#         t.start()
#     for t in t_list:
#         t.join()
#     end = time.time()
#     # print('多线程',end-start) # 多线程 15.413789510726929
#     print('多进程',end-start) # 多进程 4.711405515670776

IO密集型

# # io密集型
# def work1():
#     x = 1+1
#     time.sleep(5)
#
#
# if __name__ == '__main__':
#     t_list = []
#     start = time.time()
#     for i in range(4):
#         t = Thread(target=work1)
#         # t = Process(target=work1)
#         t_list.append(t)
#         t.start()
#     for t in t_list:
#         t.join()
#     end = time.time()
#     print('多线程',end-start) #  多线程 5.002625942230225
#     # print('多进程',end-start) # 多进程 5.660863399505615