Simpy事件排序

Question

我对简单的事件和事情发生的顺序感到困惑。在下面的代码中，发件人进程生成一个事件，并给它一个唯一的序列号。接收进程正在等待此事件，并在接收到时打印序列号。代码的输出是：

Sender sent req at time 0 with num 0
Receiver Received req at time 0 with num 0
Sender sent req at time 1 with num 1
Receiver Received req at time 1 with num 1
Sender sent req at time 2 with num 2
Receiver Received req at time 2 with num 2
Sender sent req at time 3 with num 3
Receiver Received req at time 3 with num 3
Sender sent req at time 4 with num 4
Receiver Received req at time 4 with num 4

换句话说，对于发送者发送的每一个事件，接收方只被唤醒一次。然而，我不确定这是否完全安全，并将一贯这样工作。例如，在接收方可以看到相同事件两次的情况下，是否可能出现以下顺序？

1. 发送者在t0生成一个事件。接收者在t0接收到事件。
2. 发送者和接收者睡眠1次。接收者
3. 是第一个醒来的进程。它执行它的收益语句，并发现在triggered.
4. The上生成的事件仍然是t0发送者，在t0上清除事件集并生成一个新的事件。

请你能帮我准确地理解一下这份订单是如何运作的吗？

谢谢。

import simpy

class Test:

    def __init__(self, env):
        self.env = env
        self.req = env.event()
        self.ack = env.event()

        self.env.process(self.sender())
        self.env.process(self.receiver())

    def sender(self):

        num = 0

        while True:
            self.req.succeed(num)
            print('Sender sent req at time %d with num %s' % (self.env.now, num))

            # Assert req for 1 cycle
            yield self.env.timeout(1)
            self.req = self.env.event()

            num += 1

    def receiver(self):

        while True:

            val = yield self.req
            print('Receiver Received req at time %d with num %s' % (self.env.now, val))
            yield self.env.timeout(1)

env = simpy.Environment()

test = Test(env)

env.run(until=25)

Answer 1

不，您不能依赖订单事件会在滴答中发生。通常，如果您想以异步方式执行任务，则需要一个队列。在我的示例中，我使用simpy Stores作为消息队列。请注意，这只是演示了如何进行一些通信，并且可能需要对您要使用的sim协议进行一些更改。

import simpy

class Test:

    def __init__(self, env):
        self.env = env
        self.req = simpy.Store(env)
        self.ack = simpy.Store(env)

        self.env.process(self.sender())
        self.env.process(self.receiver())

    def sender(self):

        num = 0

        while True:

            
            req = self.env.event()
            self.req.put(req)

            print('Sender sent req at time %d with num %s' % (self.env.now, num))

            # take some time to send req
            yield self.env.timeout(1)
            req.succeed(num)

            # wait for ack
            ack = yield self.ack.get()
            print('Sender got ack at time %d' % (self.env.now))
            val = yield ack
            print('Sender ack triggered at time %d with num %s' % (self.env.now, val))

            num += 1

    def receiver(self):

        while True:

            req = yield self.req.get()
            print('Receiver Received req at time %d' % (self.env.now))
            val = yield req
            print('Receiver req triggered at time %d with num %s' % (self.env.now, val))

            ack = self.env.event()
            self.ack.put(ack)
            
            # take some time to send ack
            yield self.env.timeout(1)

            ack.succeed(val)
            print('Receiver finished sending ack at time %d with num %s' % (self.env.now, val))




env = simpy.Environment()

test = Test(env)

env.run(until=25)