简单时间事件未正确排序

Question

我试图用simpy库模拟一个网络队列，当我将到达率和服务设置为1秒（平均值为1的随机生成的指数距离）时，它可以正常工作。但是，当我将到达率设置为比服务率快9倍时（即到达率=9pkts/sec，服务率=1pkt/sec），simpy进程无法正确打印（按及时顺序）

示例：

packet0 1219 arriving at 0.000000    
packet1 3568 arriving at 0.150441
packet2 3194 arriving at 0.300072
packet3 783 arriving at 0.303343
packet4 1308 arriving at 0.622341
packet5 150 arriving at 0.879188
packet6 353 arriving at 0.949535
packet7 1066 arriving at 1.036728
packet8 305 arriving at 1.038195
**packet0 1219 depart at 1.585690**
**packet1 3568 depart at 3.644606**
**packet9 3101 arriving at 1.074615**
packet10 217 arriving at 1.235867
packet11 186 arriving at 1.413119
packet12 169 arriving at 1.519886
packet2 3194 depart at 4.864265
packet13 2563 arriving at 1.520083

请注意，在****之间，进程不会在时间线内打印。有解决办法吗？谢谢

编辑为包含代码：

NEW_CUSTOMERS = 100  # Total number of customers
INTERVAL_CUSTOMERS = 0.111111  # Generate new customers roughly every x         seconds
SIZE = 1250

def source(env, number, interval, port):
    """Source generates customers randomly"""
    for i in range(number):
        size =  int(random.expovariate(0.0008))
        packet = Packet(env, '%d' % i, size, port, time_in_port=1)
        env.process(packet)
        t = random.expovariate(1 / interval)
        yield env.timeout(t)

def Packet(env, id, size, port, time_in_port):
    arrive = env.now
    yield Queue.buffer.put(size)
    print('packet%s %s arriving at %lf' % (id, size, arrive))

    with port.request() as req:
        yield req

        tip = random.expovariate(1/time_in_port)
        yield env.timeout(tip)
        amount = size
        yield Queue.buffer.get(amount)
        print('packet%s %s depart at %lf' % (id, size, env.now))

class queue:
    def __init__(self, env):
        self.buffer = simpy.Container(env, init = 0, capacity=12500)

random.seed(RANDOM_SEED)
env = simpy.Environment()
Queue = queue(env)

# Start processes and run
port = simpy.Resource(env, capacity=1)
env.process(source(env, NEW_CUSTOMERS, INTERVAL_CUSTOMERS, port))
env.run()