Python3 Processes and Threads

Processes and Threads

1. Process: Memory independent, thread sharing memory of the same process
2. A process is a collection of resources, a thread is an execution unit
3. Processes cannot directly access each other, and processes in the same process can communicate with each other
4. Create a new process consumes system resources, threads are very lightweight, saving only the necessary data when the thread is running, such as context, program stack information
5. Threads in the same process can control each other, and the parent process can control the child process

1 ImportThreading2 Import Time3 4 defsayhi (num):5     Print('Num:', num)6Time.sleep (3)7 8A = Threading. Thread (target=sayhi,args= (1,))9b = Threading. Thread (target=sayhi,args= (2,))TenNow1 =time.time () One Print(NOW1) A A.start () - B.start () -Now2 =time.time () the Print(NOW2) - Print(Threading.active_count ()) - #includes main thread, total 3 - Print(A.getname ()) + Print(B.getname ()) -  + classMyThread (Threading. Thread): A     def __init__(self,n): atThreading. Thread.__init__(self) -SELF.N =N -  -         defRun (self): -             Print('running on thread $s'%SELF.N) -Time.sleep (3) inNOW3 =time.time () - Print(NOW3) toT1 = MyThread (1) +T2 = MyThread (2) - T1.start () the T2.start () * Print(T1.getname ()) $ Print(T2.getname ())Panax NotoginsengNOW4 =time.time () - Print(NOW4) the  +Thread_list = [] A  forIinchRange (10): theS1 = Threading. Thread (target=sayhi,args=(i,)) + S1.start () - thread_list.append (S1) $NOW5 =time.time () $ Print(NOW5) -  forRinchthread_list: -R.join ()#s1.wait () the Print('--work done--') -NOW6 =time.time ()Wuyi Print(NOW6) the Print('Primary'. Center (20,'-')) -  Wu  -  forIiinchRange (10): AboutS2 = Threading. Thread (target=sayhi) $ S2.setdaemon (S2) -S2.start ()

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Python3 processes and Threads