From f87711b2daf083e42708d6dd1143cbb72616e8a0 Mon Sep 17 00:00:00 2001
From: Joakim Erdfelt <joakim.erdfelt@gmail.com>
Date: Thu, 16 Jul 2020 13:30:47 -0500
Subject: [PATCH] Adding jmh test to compare String.substring() vs
 String.repeat()

Signed-off-by: Joakim Erdfelt <joakim.erdfelt@gmail.com>
---
 .../jetty/logging/jmh/IndentBenchmark.java    | 86 +++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 tests/jetty-jmh/src/main/java/org/eclipse/jetty/logging/jmh/IndentBenchmark.java

diff --git a/tests/jetty-jmh/src/main/java/org/eclipse/jetty/logging/jmh/IndentBenchmark.java b/tests/jetty-jmh/src/main/java/org/eclipse/jetty/logging/jmh/IndentBenchmark.java
new file mode 100644
index 00000000000..913716707c4
--- /dev/null
+++ b/tests/jetty-jmh/src/main/java/org/eclipse/jetty/logging/jmh/IndentBenchmark.java
@@ -0,0 +1,86 @@
+//
+// ========================================================================
+// Copyright (c) 1995-2020 Mort Bay Consulting Pty Ltd and others.
+//
+// This program and the accompanying materials are made available under
+// the terms of the Eclipse Public License 2.0 which is available at
+// https://www.eclipse.org/legal/epl-2.0
+//
+// This Source Code may also be made available under the following
+// Secondary Licenses when the conditions for such availability set
+// forth in the Eclipse Public License, v. 2.0 are satisfied:
+// the Apache License v2.0 which is available at
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+// ========================================================================
+//
+
+package org.eclipse.jetty.logging.jmh;
+
+import java.util.concurrent.TimeUnit;
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Measurement;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.annotations.Threads;
+import org.openjdk.jmh.annotations.Warmup;
+import org.openjdk.jmh.infra.Blackhole;
+import org.openjdk.jmh.profile.GCProfiler;
+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;
+
+@State(Scope.Benchmark)
+@Threads(4)
+@Warmup(iterations = 7, time = 500, timeUnit = TimeUnit.MILLISECONDS)
+@Measurement(iterations = 7, time = 500, timeUnit = TimeUnit.MILLISECONDS)
+public class IndentBenchmark
+{
+    private static final int SMALL = 13;
+    private static final int LARGE = 43;
+    private String bigstring = "                                                                                    ";
+
+    @Benchmark
+    @BenchmarkMode(Mode.Throughput)
+    public void testStringSubStringSmall(Blackhole blackhole)
+    {
+        blackhole.consume(bigstring.substring(0, SMALL));
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.Throughput)
+    public void testStringSubStringLarge(Blackhole blackhole)
+    {
+        blackhole.consume(bigstring.substring(0, LARGE));
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.Throughput)
+    public void testStringRepeatSmall(Blackhole blackhole)
+    {
+        blackhole.consume(" " .repeat(SMALL));
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.Throughput)
+    public void testStringRepeatLarge(Blackhole blackhole)
+    {
+        blackhole.consume(" " .repeat(LARGE));
+    }
+
+    public static void main(String[] args) throws RunnerException
+    {
+        Options opt = new OptionsBuilder()
+            .include(IndentBenchmark.class.getSimpleName())
+            .addProfiler(GCProfiler.class)
+            .forks(1)
+            .build();
+
+        new Runner(opt).run();
+    }
+}