在這篇文章中：

• 使用JMH和JLBH進(jìn)行日期序列化的并排示例
• 在微基準(zhǔn)中測(cè)量日期序列化
• 測(cè)量日期序列化作為適當(dāng)應(yīng)用程序的一部分
• 如何為您的JLBH基準(zhǔn)添加探針
• 了解在上下文中衡量代碼的重要性

在上一篇文章“ JLBH簡(jiǎn)介 ”中，我們介紹了JLBH（ Chronicle用于測(cè)試Chronicle-FIX的延遲測(cè)試工具），現(xiàn)在可以作為開(kāi)源使用。

在接下來(lái)的幾篇文章中，我們將看一些示例應(yīng)用程序：

為例子甘蔗的所有代碼被發(fā)現(xiàn)這里在我的GitHub項(xiàng)目：

我在JLBH簡(jiǎn)介中提出的觀點(diǎn)之一是，在上下文中對(duì)代碼進(jìn)行基準(zhǔn)測(cè)試很重要。 這意味著在盡可能接近實(shí)際運(yùn)行環(huán)境的環(huán)境中對(duì)代碼進(jìn)行基準(zhǔn)測(cè)試。 這篇文章在實(shí)踐中演示了這一點(diǎn)。

讓我們看一下一個(gè)相對(duì)昂貴的Java操作–日期序列化–并查看需要花費(fèi)多長(zhǎng)時(shí)間：

首先，這是JMH基準(zhǔn)：

package org.latency.serialisation.date;import net.openhft.affinity.Affinity; import net.openhft.chronicle.core.Jvm; import net.openhft.chronicle.core.OS; import org.openjdk.jmh.annotations.*; import org.openjdk.jmh.runner.Runner; import org.openjdk.jmh.runner.RunnerException; import org.openjdk.jmh.runner.options.Options; import org.openjdk.jmh.runner.options.OptionsBuilder; import org.openjdk.jmh.runner.options.TimeValue;import java.io.*; import java.lang.reflect.InvocationTargetException; import java.util.Date; import java.util.concurrent.TimeUnit;/*** Created to show the effects of running code within more complex code.* Date serialisation as a micro benchmark vs date serialisation inside a TCP call.*/ @State(Scope.Thread) public class DateSerialiseJMH {private final Date date = new Date();public static void main(String[] args) throws InvocationTargetException,IllegalAccessException, RunnerException, IOException, ClassNotFoundException {if (OS.isLinux())Affinity.setAffinity(2);if(Jvm.isDebug()){DateSerialiseJMH jmhParse = new DateSerialiseJMH();jmhParse.test();}else {Options opt = new OptionsBuilder().include(DateSerialiseJMH.class.getSimpleName()).warmupIterations(6).forks(1).measurementIterations(5).mode(Mode.SampleTime).measurementTime(TimeValue.seconds(3)).timeUnit(TimeUnit.MICROSECONDS).build();new Runner(opt).run();}}@Benchmarkpublic Date test() throws IOException, ClassNotFoundException {ByteArrayOutputStream out = new ByteArrayOutputStream();ObjectOutputStream oos = new ObjectOutputStream(out);oos.writeObject(date);ObjectInputStream ois = new ObjectInputStream(new ByteArrayInputStream(out.toByteArray()));return (Date)ois.readObject();} }

在我的筆記本電腦（MBP i7）上運(yùn)行，這些是我得到的結(jié)果：

Result "test":4.578 ±(99.9%) 0.046 us/op [Average](min, avg, max) = (3.664, 4.578, 975.872), stdev = 6.320CI (99.9%): [4.533, 4.624] (assumes normal distribution)Samples, N = 206803mean = 4.578 ±(99.9%) 0.046 us/opmin = 3.664 us/opp( 0.0000) = 3.664 us/opp(50.0000) = 4.096 us/opp(90.0000) = 5.608 us/opp(95.0000) = 5.776 us/opp(99.0000) = 8.432 us/opp(99.9000) = 24.742 us/opp(99.9900) = 113.362 us/opp(99.9990) = 847.245 us/opp(99.9999) = 975.872 us/opmax = 975.872 us/op# Run complete. Total time: 00:00:21Benchmark Mode Cnt Score Error UnitsDateSerialiseJMH.test sample 206803 4.578 ± 0.046 us/op

該操作的平均時(shí)間為4.5us：
使用JLBH進(jìn)行測(cè)試時(shí)，我們得到的結(jié)果幾乎相同：

package org.latency.serialisation.date;import net.openhft.chronicle.core.jlbh.JLBHOptions; import net.openhft.chronicle.core.jlbh.JLBHTask; import net.openhft.chronicle.core.jlbh.JLBH;import java.io.*; import java.lang.reflect.InvocationTargetException; import java.util.Date;/*** Created to show the effects of running code within more complex code.* Date serialisation as a micro benchmark vs date serialisation inside a TCP call.*/ public class DateSerialisedJLBHTask implements JLBHTask {private Date date = new Date();private JLBH lth;public static void main(String[] args) throws InvocationTargetException, IllegalAccessException, IOException, ClassNotFoundException {JLBHOptions jlbhOptions = new JLBHOptions().warmUpIterations(400_000).iterations(1_000_000).throughput(100_000).runs(3).recordOSJitter(true).accountForCoordinatedOmmission(true).jlbhTask(new DateSerialisedJLBHTask());new JLBH(jlbhOptions).start();}@Overridepublic void run(long startTimeNS) {try {ByteArrayOutputStream out = new ByteArrayOutputStream();ObjectOutputStream oos = new ObjectOutputStream(out);oos.writeObject(date);ObjectInputStream ois = new ObjectInputStream(new ByteArrayInputStream(out.toByteArray()));date = (Date)ois.readObject();lth.sample(System.nanoTime() - startTimeNS);} catch (IOException | ClassNotFoundException e) {e.printStackTrace();}}@Overridepublic void init(JLBH lth) {this.lth = lth;} }

結(jié)果如下：

Warm up complete (400000 iterations took 2.934s) -------------------------------- BENCHMARK RESULTS (RUN 1) --------- Run time: 10.0s Correcting for co-ordinated:true Target throughput:100000/s = 1 message every 10us End to End: (1,000,000) 50/90 99/99.9 99.99/99.999 - worst was 4.2 / 5.8 352 / 672 803 / 901 - 934 OS Jitter (13,939) 50/90 99/99.9 99.99 - worst was 8.4 / 17 639 / 4,130 12,850 - 20,450 -------------------------------------------------------------------- -------------------------------- BENCHMARK RESULTS (RUN 2) --------- Run time: 10.0s Correcting for co-ordinated:true Target throughput:100000/s = 1 message every 10us End to End: (1,000,000) 50/90 99/99.9 99.99/99.999 - worst was 4.2 / 5.8 434 / 705 836 / 934 - 967 OS Jitter (11,016) 50/90 99/99.9 99.99 - worst was 8.4 / 17 606 / 770 868 - 1,340 -------------------------------------------------------------------- -------------------------------- BENCHMARK RESULTS (RUN 3) --------- Run time: 10.0s Correcting for co-ordinated:true Target throughput:100000/s = 1 message every 10us End to End: (1,000,000) 50/90 99/99.9 99.99/99.999 - worst was 4.2 / 5.8 434 / 737 901 / 999 - 1,030 OS Jitter (12,319) 50/90 99/99.9 99.99 - worst was 8.4 / 15 573 / 737 803 - 901 ---------------------------------------------------------------------------------------------------- SUMMARY (end to end)---------------Percentile run1 run2 run3 % Variation 50: 4.22 4.22 4.22 0.00 90: 5.76 5.76 5.76 0.00 99: 352.26 434.18 434.18 0.00 99.9: 671.74 704.51 737.28 3.01 99.99: 802.82 835.58 901.12 4.97 worst: 901.12 933.89 999.42 4.47 --------------------------------------------------------------------

該操作的平均時(shí)間為4.2us：

注意：在這種情況下，使用JLBH相對(duì)于JMH沒(méi)有優(yōu)勢(shì)。 我只是將代碼作為比較。
現(xiàn)在我們將運(yùn)行完全相同的操作，但是在TCP調(diào)用中，代碼將像這樣工作：

客戶(hù)端通過(guò)TCP回送（本地主機(jī)）向服務(wù)器發(fā)送修復(fù)消息

服務(wù)器讀取消息

服務(wù)器執(zhí)行日期序列化

服務(wù)器向客戶(hù)端返回一條消息

如前一篇文章所述，JLBH允許我們?yōu)榇a的任何部分生成延遲配置文件。 我們將為階段3添加一個(gè)探針。

package org.latency.serialisation.date;import net.openhft.affinity.Affinity; import net.openhft.chronicle.core.Jvm; import net.openhft.chronicle.core.jlbh.JLBHOptions; import net.openhft.chronicle.core.jlbh.JLBHTask; import net.openhft.chronicle.core.jlbh.JLBH; import net.openhft.chronicle.core.util.NanoSampler;import java.io.*; import java.net.InetSocketAddress; import java.nio.ByteBuffer; import java.nio.ByteOrder; import java.nio.channels.ServerSocketChannel; import java.nio.channels.SocketChannel; import java.util.Date;/*** Created to show the effects of running code within more complex code.* Date serialisation as a micro benchmark vs date serialisation inside a TCP call.*/ public class DateSerialiseJLBHTcpTask implements JLBHTask {private final static int port = 8007;private static final boolean BLOCKING = false;private final int SERVER_CPU = Integer.getInteger("server.cpu", 0);private Date date = new Date();private JLBH lth;private ByteBuffer bb;private SocketChannel socket;private byte[] fixMessageBytes;private NanoSampler dateProbe;public static void main(String[] args) {JLBHOptions lth = new JLBHOptions().warmUpIterations(50_000).iterations(100_000).throughput(20_000).runs(3).recordOSJitter(true).accountForCoordinatedOmmission(true).jlbhTask(new DateSerialiseJLBHTcpTask());new JLBH(lth).start();}@Overridepublic void init(JLBH lth) {this.lth = lth;dateProbe = lth.addProbe("date serialisation ");try {runServer(port);Jvm.pause(200);socket = SocketChannel.open(new InetSocketAddress(port));socket.socket().setTcpNoDelay(true);socket.configureBlocking(BLOCKING);} catch (IOException e) {e.printStackTrace();}String fixMessage = "8=FIX.4.2\u00019=211\u000135=D\u000134=3\u000149=MY-INITIATOR-SERVICE\u000152=20160229-" +"09:04:14.459\u000156=MY-ACCEPTOR-SERVICE\u00011=ABCTEST1\u000111=863913604164909\u000121=3\u000122=5" +"\u000138=1\u000140=2\u000144=200\u000148=LCOM1\u000154=1\u000155=LCOM1\u000159=0\u000160=20160229-09:" +"04:14.459\u0001167=FUT\u0001200=201106\u000110=144\u0001\n";fixMessageBytes = fixMessage.getBytes();int length = fixMessageBytes.length;bb = ByteBuffer.allocateDirect(length).order(ByteOrder.nativeOrder());bb.put(fixMessageBytes);}private void runServer(int port) throws IOException {new Thread(() -> {if (SERVER_CPU > 0) {System.out.println("server cpu: " + SERVER_CPU);Affinity.setAffinity(SERVER_CPU);}ServerSocketChannel ssc = null;SocketChannel socket = null;try {ssc = ServerSocketChannel.open();ssc.bind(new InetSocketAddress(port));System.out.println("listening on " + ssc);socket = ssc.accept();socket.socket().setTcpNoDelay(true);socket.configureBlocking(BLOCKING);System.out.println("Connected " + socket);ByteBuffer bb = ByteBuffer.allocateDirect(32 * 1024).order(ByteOrder.nativeOrder());for (; ; ) {bb.limit(12);do {if (socket.read(bb) < 0)throw new EOFException();} while (bb.remaining() > 0);int length = bb.getInt(0);bb.limit(length);do {if (socket.read(bb) < 0)throw new EOFException();} while (bb.remaining() > 0);long now = System.nanoTime();try {//Running the date serialisation but this time inside the TCP callback.ByteArrayOutputStream out = new ByteArrayOutputStream();ObjectOutputStream oos = new ObjectOutputStream(out);oos.writeObject(date);ObjectInputStream ois = new ObjectInputStream(new ByteArrayInputStream(out.toByteArray()));date = (Date)ois.readObject();dateProbe.sampleNanos(System.nanoTime() - now);} catch (IOException | ClassNotFoundException e) {e.printStackTrace();}bb.flip();if (socket.write(bb) < 0)throw new EOFException();bb.clear();}} catch (IOException e) {e.printStackTrace();} finally {System.out.println("... disconnected " + socket);try {if (ssc != null)ssc.close();} catch (IOException ignored) {}try {if (socket != null)socket.close();} catch (IOException ignored) {}}}, "server").start();}@Overridepublic void run(long startTimeNs) {bb.position(0);bb.putInt(bb.remaining());bb.putLong(startTimeNs);bb.position(0);writeAll(socket, bb);bb.position(0);try {readAll(socket, bb);} catch (IOException e) {e.printStackTrace();}bb.flip();if (bb.getInt(0) != fixMessageBytes.length) {throw new AssertionError("read error");}lth.sample(System.nanoTime() - startTimeNs);}private static void readAll(SocketChannel socket, ByteBuffer bb) throws IOException {bb.clear();do {if (socket.read(bb) < 0)throw new EOFException();} while (bb.remaining() > 0);}private static void writeAll(SocketChannel socket, ByteBuffer bb) {try {while (bb.remaining() > 0 && socket.write(bb) >= 0) ;} catch (IOException e) {e.printStackTrace();}} }

這次的結(jié)果如下所示：

Warm up complete (50000 iterations took 3.83s) -------------------------------- BENCHMARK RESULTS (RUN 1) ------------------------ Run time: 6.712s Correcting for co-ordinated:true Target throughput:20000/s = 1 message every 50us End to End: (100,000) 50/90 99/99.9 99.99 - worst was 822,080 / 1,509,950 1,711,280 / 1,711,280 1,711,280 - 1,711,280 date serialisation (100,000) 50/90 99/99.9 99.99 - worst was 11 / 19 31 / 50 901 - 2,420 OS Jitter (64,973) 50/90 99/99.9 99.99 - worst was 8.1 / 16 40 / 1,540 4,850 - 18,350 -------------------------------------------------------------------- -------------------------------- BENCHMARK RESULTS (RUN 2) --------- Run time: 6.373s Correcting for co-ordinated:true Target throughput:20000/s = 1 message every 50us End to End: (100,000) 50/90 99/99.9 99.99 - worst was 1,107,300 / 1,375,730 1,375,730 / 1,375,730 1,375,730 - 1,375,730 date serialisation (100,000) 50/90 99/99.9 99.99 - worst was 11 / 19 29 / 52 901 - 1,670 OS Jitter (40,677) 50/90 99/99.9 99.99 - worst was 8.4 / 16 34 / 209 934 - 1,470 -------------------------------------------------------------------- -------------------------------- BENCHMARK RESULTS (RUN 3) --------- Run time: 5.333s Correcting for co-ordinated:true Target throughput:20000/s = 1 message every 50us End to End: (100,000) 50/90 99/99.9 99.99 - worst was 55,570 / 293,600 343,930 / 343,930 343,930 - 343,930 date serialisation (100,000) 50/90 99/99.9 99.99 - worst was 9.0 / 16 26 / 38 770 - 1,030 OS Jitter (32,042) 50/90 99/99.9 99.99 - worst was 9.0 / 13 22 / 58 737 - 934 -------------------------------------------------------------------- -------------------------------- SUMMARY (end to end)--------------- Percentile run1 run2 run3 % Variation 50: 822083.58 1107296.26 55574.53 92.66 90: 1509949.44 1375731.71 293601.28 71.07 99: 1711276.03 1375731.71 343932.93 66.67 99.9: 1711276.03 1375731.71 343932.93 66.67 99.99: 1711276.03 1375731.71 343932.93 66.67 worst: 1711276.03 1375731.71 343932.93 66.67 -------------------------------------------------------------------- -------------------------------- SUMMARY (date serialisation )------ Percentile run1 run2 run3 % Variation 50: 11.01 11.01 8.96 13.22 90: 18.94 18.94 15.62 12.44 99: 31.23 29.18 26.11 7.27 99.9: 50.18 52.22 37.89 20.14 99.99: 901.12 901.12 770.05 10.19 worst: 2424.83 1671.17 1032.19 29.21 --------------------------------------------------------------------

可以看出，相同的日期序列化從?4.5us到?10us的時(shí)間是原來(lái)的兩倍。

并不是在這里詳細(xì)討論為什么代碼在上下文中運(yùn)行需要花費(fèi)更長(zhǎng)的時(shí)間，但這與在日期序列調(diào)用之間填充CPU緩存有關(guān)。

當(dāng)我們運(yùn)行時(shí)（如微型基準(zhǔn)測(cè)試中一樣）是日期序列化，那么它可以很好地裝入CPU緩存中，而無(wú)需清除。 但是，當(dāng)對(duì)日期序列化的調(diào)用之間存在間隙時(shí)，該操作的代碼將被清除并需要重新加載。

JLBH允許您在上下文中對(duì)代碼進(jìn)行基準(zhǔn)測(cè)試，這是延遲基準(zhǔn)測(cè)試的重要組成部分。

翻譯自: https://www.javacodegeeks.com/2016/04/jlbh-examples-1-code-benchmarked-context.html

總結(jié)

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