python threads and processes Learning Notes

Multithreaded vs multiprocess

• Program: a bunch of code into a document as text
• Process: a state program running
  • Contains the address space, memory, and other data stack
  • Each process is completed by its own independent operating environment, multiple processes to share data is a problem
• Thread
  • Stand-alone segment of a process, a process can have multiple threads
  • Lightweight process
  • Between multiple threads of a process share data and context operating environment
  • Shared Exclusive issue
• Global Interpreter Lock (GIL)
  • Python code execution is controlled by a virtual machine python
  • There is a thread of control executed in the main loop

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threading of use

• Thread exemplary generated directly threading.Thread
  1. t = threading.Thread(target=xxx, args=(xxx,))
  2. t.start (): Start multithreading
  3. t.join (): <font color = red> multithreaded execution waiting completion </ font>
• Case 01:

import threading
import time

def loop01(in01):
print("start loop01 at : {0}".format(time.ctime()))
print("loop01参数:{0}".format(in01))
time.sleep(4)
print("end loop01 at : {0}".format(time.ctime()))

loop02 DEF (IN01, IN02):
Print ( 'Start loop02 AT: {0}'. the format (time.ctime ()))
Print ( "loop02 parameter, the first parameter {0}, {1} the second parameter ".format (IN01, IN02))
the time.sleep (2)
Print (" End loop02 AT:. {0} "the format (time.ctime ()))

if name == 'main':
print("Starting at : {0}".format(time.ctime()))
t1 = threading.Thread(target=loop01,args=("loop01参数",))
t2 = threading.Thread(target=loop02,args=("loop02参数1","loop02参数2"))
t1.start()
t2.start()
t1.join()
t2.join()
print("All done at {0}".format(time.ctime()))
while True:
time.sleep(10)