Python 线程中加锁范围如何选择：大范围加锁还是小范围加锁更优？

from threading import thread, lockimport timenum = 0def test1():    global num    # 上锁    mutex.acquire()    for i in range(1000000):        num += 1    # 解锁    mutex.release()    print("--test1--num=%d" % num)def test2():    global num    mutex.acquire()    for i in range(1000000):        num += 1    mutex.release()    print("--test2--num=%d" % num)

--test1--num=1890838--test2--num=2000000num = 2000000运行时间:4.694896s

--test1--num=1000000--test2--num=2000000num = 2000000运行时间:0.287206s