Added benchmark to measure Tags.and(Tags) operation.

benchmarks/benchmarks-core/src/jmh/java/io/micrometer/benchmark/core/TagsMergeBenchmark.java

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2018 VMware, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.micrometer.benchmark.core;
+
+import io.micrometer.core.instrument.Tags;
+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 java.util.concurrent.TimeUnit;
+
+@Fork(1)
+@Measurement(iterations = 2)
+@Warmup(iterations = 2)
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.NANOSECONDS)
+@State(Scope.Thread)
+public class TagsMergeBenchmark {
+
+    Tags left = Tags.of("key", "value", "key2", "value2", "key6", "value6", "key7", "value7", "key8", "value8", "keyA",
+            "valueA", "keyC", "valueC", "keyE", "valueE", "keyF", "valueF", "keyG", "valueG", "keyG", "valueG", "keyG",
+            "valueG", "keyH", "valueH");
+
+    Tags right = Tags.of("key", "value", "key1", "value1", "key2", "value2", "key3", "value3", "key4", "value4", "key5",
+            "value5", "keyA", "valueA", "keyB", "valueB", "keyD", "valueD");
+
+    @Threads(16)
+    @Benchmark
+    public Tags mergeTags() {
+        return left.and(right);
+    }
+
+    public static void main(String[] args) throws RunnerException {
+        Options opt = new OptionsBuilder().include(TagsMergeBenchmark.class.getSimpleName()).build();
+        new Runner(opt).run();
+    }
+
+}