山东住房和城乡建设厅网站电话,wordpress 2015主题公园,怎么自己做网站赚钱吗,网站里的地图定位怎么做在这篇文章中#xff0c;我演示了许多想法和技术#xff1a; 如何编写一个简单的非阻塞NIO客户端/服务器 协调遗漏的影响 如何测量百分位数的延迟#xff08;相对于简单平均#xff09; 如何在计算机上计时延迟回送 我最近正在为客户端服务器应用程序开发低延迟基准测… 在这篇文章中我演示了许多想法和技术 如何编写一个简单的非阻塞NIO客户端/服务器 协调遗漏的影响 如何测量百分位数的延迟相对于简单平均 如何在计算机上计时延迟回送 我最近正在为客户端服务器应用程序开发低延迟基准测试。 最初我在使用环回TCP的单台计算机上模拟基准测试。 我要量化的第一个指标是允许简单的环回延迟需要多少记录延迟。 这样我便可以更清楚地了解实际应用程序增加的延迟。 为此我创建了一个程序文章末尾的代码该程序将一个字节从客户端传输到服务器然后再传输回来。 重复执行此操作并处理结果。 该程序是使用非阻塞Java NIO编写的以尽可能优化回送延迟。 比记录平均时间更重要的是记录了百分比延迟。 有关如何测量延迟的讨论请参见此处的上一篇文章。 至关重要的是协调遗漏的代码因素。 要了解更多关于此看到这里从吉尔·特内。 简而言之您不会从开始时就开始计时而应该从开始就开始。 这些是我2岁的MBP的结果。 Starting latency test rate: 80000
Average time 2513852
Loop back echo latency was 2514247.3/3887258.6 4,196,487/4,226,913 4,229,987/4230294 4,230,294 us for 50/90 99/99.9 99.99/99.999 worst %tile
Starting latency test rate: 70000
Average time 2327041
Loop back echo latency was 2339701.6/3666542.5 3,957,860/3,986,626 3,989,404/3989763 3,989,763 us for 50/90 99/99.9 99.99/99.999 worst %tile
Starting latency test rate: 50000
Average time 1883303
Loop back echo latency was 1881621.0/2960104.0 3,203,771/3,229,260 3,231,809/3232046 3,232,046 us for 50/90 99/99.9 99.99/99.999 worst %tile
Starting latency test rate: 30000
Average time 1021576
Loop back echo latency was 1029566.5/1599881.0 1,726,326/1,739,626 1,741,098/1741233 1,741,233 us for 50/90 99/99.9 99.99/99.999 worst %tile
Starting latency test rate: 20000
Average time 304
Loop back echo latency was 65.6/831.2 3,632/4,559 4,690/4698 4,698 us for 50/90 99/99.9 99.99/99.999 worst %tile
Starting latency test rate: 10000
Average time 50
Loop back echo latency was 47.8/57.9 89/120 152/182 182 us for 50/90 99/99.9 99.99/99.999 worst %tile 将这些结果与我没有纠正遗漏的情况进行比较 Starting latency test rate: 80000
Average time 45
Loop back echo latency was 44.1/48.8 71/105 124/374 374 us for 50/90 99/99.9 99.99/99.999 worst %tile
Starting latency test rate: 70000
Average time 45
Loop back echo latency was 44.1/48.9 76/106 145/358 358 us for 50/90 99/99.9 99.99/99.999 worst %tile
Starting latency test rate: 50000
Average time 45
Loop back echo latency was 43.9/48.8 74/105 123/162 162 us for 50/90 99/99.9 99.99/99.999 worst %tile
Starting latency test rate: 30000
Average time 45
Loop back echo latency was 44.0/48.8 73/104 129/147 147 us for 50/90 99/99.9 99.99/99.999 worst %tile
Starting latency test rate: 20000
Average time 45
Loop back echo latency was 44.7/49.6 78/107 135/311 311 us for 50/90 99/99.9 99.99/99.999 worst %tile
Starting latency test rate: 10000
Average time 46
Loop back echo latency was 45.1/50.8 81/112 144/184 184 us for 50/90 99/99.9 99.99/99.999 worst %tile 如您所见吞吐量的影响被完全忽略了 看起来即使以每秒80,000条消息的速度运行您的99.99个百分位数仍为374us而实际上却远大于此。 实际上只有在吞吐量接近每秒10,000时您才能达到目标延迟。 如您所直观地理解的那样在吞吐量和延迟之间需要权衡取舍。 该测试的代码如下 package util;import java.io.EOFException;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.nio.ByteBuffer;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Arrays;/*** Created by daniel on 02/07/2015.* Simple program to test loopback speeds and latencies.*/
public class LoopBackPingPong {public final static int PORT 8007;public void runServer(int port) throws IOException {ServerSocketChannel ssc ServerSocketChannel.open();ssc.bind(new InetSocketAddress(port));System.out.println(listening on ssc);final SocketChannel socket ssc.accept();socket.socket().setTcpNoDelay(true);socket.configureBlocking(false);new Thread(() - {long totalTime 0;int count 0;try {System.out.println(Connected socket);ByteBuffer bb ByteBuffer.allocateDirect(1);int length;while ((length socket.read(bb)) 0) {if (length 0) {long time System.nanoTime();bb.flip();bb.position(0);count;if (socket.write(bb) 0)throw new EOFException();bb.clear();totalTime System.nanoTime() - time;}}} catch (IOException ignored) {} finally {System.out.println(Total server time (totalTime / count) / 1000);System.out.println(... disconnected socket);try {socket.close();} catch (IOException ignored) {}}}).start();}public void testLatency(int targetThroughput, SocketChannel socket) throws IOException {System.out.println(Starting latency test rate: targetThroughput);int tests Math.min(18 * targetThroughput, 100_000);long[] times new long[tests];int count 0;long now System.nanoTime();long rate (long) (1e9 / targetThroughput);ByteBuffer bb ByteBuffer.allocateDirect(4);bb.putInt(0, 0x12345678);for (int i -20000; i tests; i) {//now rate;//while (System.nanoTime() now)// ;now System.nanoTime();bb.position(0);while (bb.remaining() 0)if (socket.write(bb) 0)throw new EOFException();bb.position(0);while (bb.remaining() 0)if (socket.read(bb) 0)throw new EOFException();if (bb.getInt(0) ! 0x12345678)throw new AssertionError(read error);if (i 0)times[count] System.nanoTime() - now;}System.out.println(Average time (Arrays.stream(times).sum() / times.length) / 1000);Arrays.sort(times);System.out.printf(Loop back echo latency was %.1f/%.1f %,d/%,d %,d/%d %,d us for 50/90 99/99.9 99.99/99.999 worst %%tile%n,times[times.length / 2] / 1e3,times[times.length * 9 / 10] / 1e3,times[times.length - times.length / 100] / 1000,times[times.length - times.length / 1000] / 1000,times[times.length - times.length / 10000] / 1000,times[times.length - times.length / 100000] / 1000,times[times.length - 1] / 1000);}public static void main(String... args) throws Exception {int port args.length 1 ? PORT : Integer.parseInt(args[0]);LoopBackPingPong lbpp new LoopBackPingPong();new Thread(() - {try {lbpp.runServer(port);} catch (IOException e) {Jvm.rethrow(e);}}).start();//give the server a chance to startThread.sleep(1000);SocketChannel socket SocketChannel.open(new InetSocketAddress(localhost, port));socket.socket().setTcpNoDelay(true);socket.configureBlocking(false);for (int i : new int[]{80_000, 70_000, 50_000, 30_000, 20_000, 10_000})lbpp.testLatency(i, socket);System.exit(0);}}翻译自: https://www.javacodegeeks.com/2015/07/the-effect-of-co-ordinated-omission-measure-loopback-latency-using-a-simple-nio-clientserver.html
