Count += 1 不是原子级的

done_num = 0
lock = threading.RLock()
# 省略...
class Trans(threading.Thread):
    def run(self):
        global count
        # ...
        lock.acquire()
        count += 1
        lock.release()
        # ...

count = 0

class GlobalCount(threading.Thread):
    def __init__(self):
        super(GlobalCount, self).__init__()

    def run(self):
        global count
        for dummy_i in xrange(10):
            count += 1

threads = []
threads_num = 100000

for dummy_i in xrange(threads_num):
    threads.append(GlobalCount())

for thread in threads:
    thread.start()

for thread in threads:
    thread.join()

print count

999990
999982
999940

3 LOAD_CONST               1 (1)
6 INPLACE_ADD
7 STORE_GLOBAL             0 (count)