Python 多线程锁问题

程序代码：

import threading

VALUE = 0
gLOCK = threading.Lock()

class MyThread(threading.Thread):

    def __init__(self, loop_times):
        super().__init__()
        self.loop_times = loop_times

    def run(self):
        global VALUE
        for i in range(self.loop_times):
            gLOCK.acquire()
            VALUE += 1
            gLOCK.release()

        print(self.loop_times, self.name, VALUE)

if __name__ == '__main__':
    for i in range(2):
        MyThread(1000000).start()

我想知道为什么这样使用锁得不到期望的预期结果:
1000000 Thread-1 1000000
1000000 Thread-2 2000000

Python 多线程 锁 问题