add source for the performance tests I was doing on buffer size

Author: David R. MacIver

test/src/com/rabbitmq/examples/BufferPerformanceMetrics.java

@@ -0,0 +1,85 @@
+package com.rabbitmq.examples;
+
+import com.rabbitmq.client.ConnectionFactory;
+import com.rabbitmq.client.Connection;
+import com.rabbitmq.client.Channel;
+import com.rabbitmq.client.GetResponse;
+import com.rabbitmq.client.MessageProperties;
+import java.util.Arrays;
+import java.net.Socket;
+import java.io.IOException;
+import java.util.Random;
+
+/**
+ * Class to explore how performance of sending and receiving messages varies with the buffer size and 
+ * enabling/disabling Nagle's algorithm.
+ */
+public class BufferPerformanceMetrics{
+
+    public static final String QUEUE = "performance-test-queue";
+    public static final String EXCHANGE = "performance-test-exchange";
+    public static final String ROUTING_KEY = "performance-test-rk";
+    public static final int MESSAGE_COUNT = 10000;
+    public static final byte[] MESSAGE = "Hello world".getBytes();
+    public static double NANOSECONDS_PER_SECOND = 1000 * 1000 * 1000;
+    public static final int REPEATS = 1000000;
+    public static final int PEAK_SIZE = 20 * 1024;
+
+    public static void main(String[] args) throws Exception{
+        Random rnd = new Random();
+
+        System.out.println("buffer size, publish rate with nagle, get rate with nagle," + 
+            " publish rate without nagle, get rate without nagle");
+        for(int repeat = 0; repeat < REPEATS; repeat++){
+            final int bufferSize = 1 + rnd.nextInt(PEAK_SIZE);
+                 
+            double publishRateNagle = 0, publishRateNoNagle = 0, getRateNagle = 0, getRateNoNagle = 0;
+    
+            for(final boolean useNagle : new boolean[]{ false, true }){
+                ConnectionFactory factory = new ConnectionFactory(){
+                    @Override public void configureSocket(Socket socket) throws IOException{
+                        socket.setTcpNoDelay(!useNagle);
+                        socket.setReceiveBufferSize(bufferSize);
+                        socket.setSendBufferSize(bufferSize);
+                    }
+                };
+                Connection connection = factory.newConnection("localhost");
+                Channel channel = connection.createChannel();
+                channel.exchangeDeclare(EXCHANGE, "direct");
+                channel.queueDeclare(QUEUE);
+                channel.queueBind(QUEUE, EXCHANGE, ROUTING_KEY);
+             
+                long start;
+            
+                start = System.nanoTime(); 
+                for(int i = 0; i < MESSAGE_COUNT; i++){
+                    channel.basicPublish(EXCHANGE, QUEUE, MessageProperties.BASIC, MESSAGE);
+                }                 
+                long publishTime =    System.nanoTime() - start;
+
+                start = System.nanoTime(); 
+                for(int i = 0; i < MESSAGE_COUNT; i++){
+                    GetResponse response = channel.basicGet(QUEUE, true);
+                    assert(Arrays.equals(MESSAGE, response.getBody()));
+                } 
+                long getTime =    System.nanoTime() - start;
+
+                double publishRate = MESSAGE_COUNT / (publishTime / NANOSECONDS_PER_SECOND);
+                double getRate = MESSAGE_COUNT / (getTime / NANOSECONDS_PER_SECOND);
+                if(useNagle){
+                    publishRateNagle = publishRate;
+                    getRateNagle = getRate;
+                } else {
+                    publishRateNoNagle = publishRate;
+                    getRateNoNagle = getRate;
+                }
+
+                connection.close();
+                // Small sleep to remove noise from hammering the server. 
+                Thread.sleep(100);
+            }
+
+            System.out.println(bufferSize + ", " + publishRateNagle + ", " + getRateNagle + ", " + publishRateNoNagle + ", " + getRateNoNagle);
+        }
+    }
+}