1. Resource competition ：sum+=1 There are roughly three steps to execute （ Value 、 Add 1、 Write back to ）, Probably just executed 2 Step cpu I switched to another thread to execute ;
2. terms of settlement ：1. Use join() Method to set thread synchronization （ The efficiency is not high ）,2. Lock ( It can ensure that only one thread is executing at the same time ) .
'''
Resource competition ：sum+=1 There are roughly three steps to execute （ Value 、 Add 1、 Write back to ）, Probably just executed 2 Step cpu I switched to another thread to execute
terms of settlement ：1. Use join() Method to set thread synchronization （ The efficiency is not high ）,2. Lock ( It can ensure that only one thread is executing at the same time )
'''
import threading
import time
sum=0
lock=threading.Lock()
def add_num1():
global sum
for i in range(1000000):
# lock.acquire() # Lock
sum+=1
# lock.release() # Unlock
print(f'{threading.current_thread().name} The result is {sum}')
def add_num2():
global sum
for i in range(1000000):
# lock.acquire()
sum+=1
# lock.release()
print(f'{threading.current_thread().name} The result is {sum}')
if __name__ == '__main__':
t1=threading.Thread(target=add_num1)
t2=threading.Thread(target=add_num2)
t1.start()
# Set blocking function , Set thread synchronization
t1.join()
t2.start()
print(f'Main Of sum The value is {sum}')
