From 6b96b4d133528198fcaab6bdf91464b967186dba Mon Sep 17 00:00:00 2001
From: Yury Yarashevich <yura.yaroshevich@gmail.com>
Date: Thu, 23 May 2024 14:14:15 +0200
Subject: [PATCH] Check if tags array is already sorted set before sorting.

---
 .../benchmark/core/TagsBenchmark.java         | 55 +++++++++++++++++++
 .../benchmark/core/TagsMergeBenchmark.java    | 12 ++--
 .../io/micrometer/core/instrument/Tags.java   |  7 ++-
 3 files changed, 66 insertions(+), 8 deletions(-)

diff --git a/benchmarks/benchmarks-core/src/jmh/java/io/micrometer/benchmark/core/TagsBenchmark.java b/benchmarks/benchmarks-core/src/jmh/java/io/micrometer/benchmark/core/TagsBenchmark.java
index b930006011..813f0da21c 100644
--- a/benchmarks/benchmarks-core/src/jmh/java/io/micrometer/benchmark/core/TagsBenchmark.java
+++ b/benchmarks/benchmarks-core/src/jmh/java/io/micrometer/benchmark/core/TagsBenchmark.java
@@ -15,6 +15,7 @@
  */
 package io.micrometer.benchmark.core;
 
+import io.micrometer.core.instrument.Tag;
 import io.micrometer.core.instrument.Tags;
 import org.openjdk.jmh.annotations.*;
 import org.openjdk.jmh.runner.Runner;
@@ -31,6 +32,60 @@
 @OutputTimeUnit(TimeUnit.NANOSECONDS)
 public class TagsBenchmark {
 
+    static final Tag[] orderedTagsSet10 = new Tag[] { Tag.of("key0", "value"), Tag.of("key1", "value"),
+            Tag.of("key2", "value"), Tag.of("key3", "value"), Tag.of("key4", "value"), Tag.of("key5", "value"),
+            Tag.of("key6", "value"), Tag.of("key7", "value"), Tag.of("key8", "value"), Tag.of("key9", "value") };
+
+    static final Tag[] orderedTagsSet4 = new Tag[] { Tag.of("key0", "value"), Tag.of("key1", "value"),
+            Tag.of("key2", "value"), Tag.of("key3", "value"), };
+
+    static final Tag[] orderedTagsSet2 = new Tag[] { Tag.of("key0", "value"), Tag.of("key1", "value"), };
+
+    static final Tag[] unorderedTagsSet10 = new Tag[] { Tag.of("key1", "value"), Tag.of("key2", "value"),
+            Tag.of("key3", "value"), Tag.of("key4", "value"), Tag.of("key5", "value"), Tag.of("key6", "value"),
+            Tag.of("key7", "value"), Tag.of("key8", "value"), Tag.of("key9", "value"), Tag.of("key0", "value") };
+
+    static final Tag[] unorderedTagsSet4 = new Tag[] { Tag.of("key1", "value"), Tag.of("key2", "value"),
+            Tag.of("key3", "value"), Tag.of("key0", "value"), };
+
+    static final Tag[] unorderedTagsSet2 = new Tag[] { Tag.of("key1", "value"), Tag.of("key0", "value") };
+
+    @Threads(16)
+    @Benchmark
+    public Tags tagsOfOrderedTagsSet10() {
+        return Tags.of(orderedTagsSet10);
+    }
+
+    @Threads(16)
+    @Benchmark
+    public Tags tagsOfOrderedTagsSet4() {
+        return Tags.of(orderedTagsSet4);
+    }
+
+    @Threads(16)
+    @Benchmark
+    public Tags tagsOfOrderedTagsSet2() {
+        return Tags.of(orderedTagsSet2);
+    }
+
+    @Threads(16)
+    @Benchmark
+    public Tags tagsOfUnorderedTagsSet10() {
+        return Tags.of(unorderedTagsSet10);
+    }
+
+    @Threads(16)
+    @Benchmark
+    public Tags tagsOfUnorderedTagsSet4() {
+        return Tags.of(unorderedTagsSet4);
+    }
+
+    @Threads(16)
+    @Benchmark
+    public Tags tagsOfUnorderedTagsSet2() {
+        return Tags.of(unorderedTagsSet2);
+    }
+
     @Threads(16)
     @Benchmark
     public void of() {
diff --git a/benchmarks/benchmarks-core/src/jmh/java/io/micrometer/benchmark/core/TagsMergeBenchmark.java b/benchmarks/benchmarks-core/src/jmh/java/io/micrometer/benchmark/core/TagsMergeBenchmark.java
index d592f2bb3f..59a24cf89f 100644
--- a/benchmarks/benchmarks-core/src/jmh/java/io/micrometer/benchmark/core/TagsMergeBenchmark.java
+++ b/benchmarks/benchmarks-core/src/jmh/java/io/micrometer/benchmark/core/TagsMergeBenchmark.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2018 VMware, Inc.
+ * Copyright 2024 VMware, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -32,12 +32,12 @@
 @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");
+    static final 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");
+    static final 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
diff --git a/micrometer-core/src/main/java/io/micrometer/core/instrument/Tags.java b/micrometer-core/src/main/java/io/micrometer/core/instrument/Tags.java
index c91c0a90d2..4a79706b83 100644
--- a/micrometer-core/src/main/java/io/micrometer/core/instrument/Tags.java
+++ b/micrometer-core/src/main/java/io/micrometer/core/instrument/Tags.java
@@ -60,8 +60,11 @@ private static boolean isSortedSet(Tag[] sortedSet, int length) {
     }
 
     private static Tags make(Tag[] tags) {
-        Arrays.sort(tags);
-        int len = dedup(tags);
+        int len = tags.length;
+        if (!isSortedSet(tags, len)) {
+            Arrays.sort(tags);
+            len = dedup(tags);
+        }
         return new Tags(tags, len);
     }