Python multi-process multiprocessing module

Multiprocessing Common methods:

• Cpu_count (): Count CPU Cores

  Multiprocessing.cpu_count ()

• Active_children () gets all child processes

  Multiprocessing.active_children ()

• Preces () Create a Process object

  Multiprocessing. Preces (Target=function_name, args= ())

  target: 函数名args: 函数需要的参数，以tuple形式传入，一个参数时需（1，）

Preces Common methods:

• Is_alive () Determine if the process exists

• Run () Start process

• Start () starts the process and automatically calls the Run method, a common

• Join ([timeout]) waits for the process to end or until it expires
  • Join () Method Description:

  def def worker(interval):    time.sleep(interval)    print(‘hello world‘)P = multiprocessing.Process(target=worker, args=(5,))#-----------------------------------P.start()#设置timeout 设置超时时间print(P.is_alive())P.join(timeout=3)print(‘end main‘)###    True    end main    hello world#-----------------------------------P.start()P.alive()# 不调置timeout 超时时间P.join()print()###    True    hello world    end main#-----------------------------------结论：当join()不设置timeout时程序会一直等待上面的进程执行完成后再执行join()后面的代码当设置timeout时，无论上面的进程是否执行完成，程序运行到指定时间后就会执行后面的代码

  Preces Common Properties

• NAMD Process Name

• The PID of PID process

Python multi-process multiprocessing module