多线程的一点问题

def isRunning(process_name): 
        try:
            process=len(os.popen('tasklist | findstr '+process_name).readlines())
            if process >=1 :
                return True
            else:
                return False
        except:
            print("程序错误")
            return False

def task_killer():
        while 1:
            if isRunning('Taskmgr.exe'):
                os.system('taskkill /IM Taskmgr.exe')
            time.sleep(1)

以上代码用来干掉 Taskmgr.exe 进程，使用 Threading 模块的 Thread 实现多线程

t1 = threading.Thread(target=task_killer)
t1.start()

现在想问怎么终止这个线程，t1.join 没用，还会堵塞,t1.join(1)也没用，google 找了以下代码也没用

def _async_raise(tid, exctype):
    """raises the exception, performs cleanup if needed"""
    tid = ctypes.c_long(tid)
    if not inspect.isclass(exctype):
        exctype = type(exctype)
    res = ctypes.pythonapi.PyThreadState_SetAsyncExc(tid, ctypes.py_object(exctype))
    if res == 0:
        raise ValueError("invalid thread id")
    elif res != 1:
        # """if it returns a number greater than one, you're in trouble,
        # and you should call it again with exc=NULL to revert the effect"""
        ctypes.pythonapi.PyThreadState_SetAsyncExc(tid, None)
        raise SystemError("PyThreadState_SetAsyncExc failed")
 
def stop_thread(thread):
    '''强制关闭某一个线程'''
    _async_raise(thread.ident, SystemExit)

谢谢！