使用 netmq 轮询器的性能影响

Question

在下面的代码中，我使用 netmq push/pull 套接字发送和接收 100000 条消息。我首先尝试在拉式套接字上使用 ReceiveFrameString（ReceiveSimple 方法）进行简单的阻塞调用，然后尝试使用轮询器进行相同的操作（ReceiveWithPoller 方法）。

使用轮询器对发送/接收消息所需的时间有重大影响。我试图自己弄清楚为什么使用 dotTrace，我发现很多时间都花在等待 Socket.Select 执行上。

有人可以确认或解释这种差异吗？

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using NetMQ;
using NetMQ.Sockets;

namespace PushPull
{
    class Program
    {
        static int messageReceived = 0;

        const int sampleCount = 100 * 1000;

        static void Main(string[] args)
        {
            // Create psu socket
            PushSocket pushSocket = new PushSocket();
            pushSocket.Bind("tcp://localhost:5555");

            // Create pull socket
            PullSocket pullSocket = new PullSocket();
            pullSocket.Connect("tcp://localhost:5555");

            Console.WriteLine("Ready...press any key to start");
            Console.ReadKey();
            Console.WriteLine();

            // Start sending
            Task.Run(() =>
            {
                for (int i = 0; i < sampleCount; i++)
                {
                    pushSocket.SendFrame(Encoding.UTF8.GetBytes("ping"));
                }
            });

            Stopwatch sw = Stopwatch.StartNew();

            //ReceiveSimple(pullSocket);

            ReceiveWithPoller(pullSocket);

            // Display result.
            sw.Stop();
            Console.WriteLine();
            Console.WriteLine("{0} message exchanged in {1} msecs", sampleCount, sw.Elapsed.TotalMilliseconds);
        }

        private static void ReceiveSimple(PullSocket pullSocket)
        {
            messageReceived = 0;
            do
            {
                pullSocket.ReceiveFrameString();
            } while (!HandleMessage());
        }

        private static void ReceiveWithPoller(PullSocket pullSocket)
        {
            NetMQPoller poller = new NetMQPoller();
            poller.Add(pullSocket);
            pullSocket.ReceiveReady += (sender, eventArgs) =>
            {
                if (HandleMessage())
                {
                    poller.Stop();
                }
            };
            poller.Run();
        }

        private static bool HandleMessage()
        {
            messageReceived++;

            if (messageReceived % 10000 == 0)
            {
                Console.WriteLine("10k");
            }

            return messageReceived == sampleCount;
        }
    }
}

Answer 1

当您处理大量消息时，轮询器的开销很大，但有一个非常简单的解决方案。

当您收到就绪事件时获取队列中的所有消息，您可以使用 Try* 方法执行此操作，在您的示例中如下所示：

 pullSocket.ReceiveReady += (sender, eventArgs) =>
 {
    string message;
    while (pullSocket.TryReceiveFrameString(out message) 
    {
        if (HandleMessage())
        {
            poller.Stop();
        }
    }
 };

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