Avoid DistributionStatisticsConfig creation when retrieving timers (#6661)

shakuzen · web-flow · commit 84322ca547dc · 2025-08-25T19:49:40.000+09:00
In the case where the Timer/LongTaskTimer builder is not used, the DistributionStatisticsConfig is necessarily one with the default configuration being passed to registerMeterIfNecessary. We can avoid creating and configuring a DistributionStatisticsConfig that will always have the same config by keeping a static default one to use in these cases.

In performance critical areas the API to register Timer/LongTaskTimer that doesn't use the Builder should be preferred for this reason.

The usage in DefaultMeterObservationHandler has been updated accordingly, which should improve the performance and allocations for all applications using it.
diff --git a/benchmarks/benchmarks-core/build.gradle b/benchmarks/benchmarks-core/build.gradle
@@ -28,11 +28,11 @@ compileJava {
 
 dependencies {
     jmh project(':micrometer-core')
-//    jmh 'io.micrometer:micrometer-core:1.13.0-M2'
+//    jmh 'io.micrometer:micrometer-core:1.16.0-M2'
     jmh project(':micrometer-registry-prometheus')
-//    jmh 'io.micrometer:micrometer-registry-prometheus:1.13.0-M2'
+//    jmh 'io.micrometer:micrometer-registry-prometheus:1.16.0-M2'
     jmh project(':micrometer-registry-otlp')
-//    jmh 'io.micrometer:micrometer-registry-otlp:1.13.0-M2'
+//    jmh 'io.micrometer:micrometer-registry-otlp:1.16.0-M2'
 
     jmh libs.dropwizardMetricsCore5
     jmh libs.prometheusMetrics
diff --git a/benchmarks/benchmarks-core/src/jmh/java/io/micrometer/benchmark/core/MeterRegistrationBenchmark.java b/benchmarks/benchmarks-core/src/jmh/java/io/micrometer/benchmark/core/MeterRegistrationBenchmark.java
@@ -15,12 +15,11 @@
  */
 package io.micrometer.benchmark.core;
 
-import io.micrometer.core.instrument.Counter;
-import io.micrometer.core.instrument.Meter;
-import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.*;
 import io.micrometer.core.instrument.config.MeterFilter;
 import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
 import org.openjdk.jmh.annotations.*;
+import org.openjdk.jmh.annotations.Measurement;
 import org.openjdk.jmh.profile.GCProfiler;
 import org.openjdk.jmh.runner.Runner;
 import org.openjdk.jmh.runner.RunnerException;
@@ -50,6 +49,8 @@ public static void main(String[] args) throws RunnerException {
 
     Meter.MeterProvider<Counter> counterMeterProvider = Counter.builder("jmh.existing").withRegistry(registry);
 
+    Tags tags = Tags.of("key", "value");
+
     @Setup
     public void setup() {
         registry.config()
@@ -58,6 +59,17 @@ public void setup() {
         registry.counter("jmh.stale");
         registry.config().meterFilter(MeterFilter.acceptNameStartsWith("jmh"));
         registry.counter("jmh.existing", "k1", "v1");
+        registry.timer("jmh.existing.timer", tags);
+    }
+
+    @Benchmark
+    public Timer registerExistingTimer() {
+        return registry.timer("jmh.existing.timer", tags);
+    }
+
+    @Benchmark
+    public Timer registerExistingTimerBuilder() {
+        return Timer.builder("jmh.existing.timer").tags(tags).register(registry);
     }
 
     @Benchmark
diff --git a/benchmarks/benchmarks-core/src/jmh/java/io/micrometer/benchmark/core/ObservationBenchmark.java b/benchmarks/benchmarks-core/src/jmh/java/io/micrometer/benchmark/core/ObservationBenchmark.java
@@ -17,13 +17,16 @@
 
 import java.util.concurrent.TimeUnit;
 
+import io.micrometer.common.KeyValue;
+import io.micrometer.common.KeyValues;
 import io.micrometer.core.instrument.LongTaskTimer;
 import io.micrometer.core.instrument.Tags;
 import io.micrometer.core.instrument.Timer;
 import io.micrometer.core.instrument.observation.DefaultMeterObservationHandler;
 import io.micrometer.core.instrument.observation.ObservationOrTimerCompatibleInstrumentation;
 import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
 import io.micrometer.observation.Observation;
+import io.micrometer.observation.ObservationConvention;
 import io.micrometer.observation.ObservationRegistry;
 import org.openjdk.jmh.annotations.*;
 import org.openjdk.jmh.profile.GCProfiler;
@@ -34,8 +37,8 @@
 @Fork(1)
 @Threads(4)
 @State(Scope.Benchmark)
-@BenchmarkMode(Mode.SampleTime)
-@OutputTimeUnit(TimeUnit.MICROSECONDS)
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.NANOSECONDS)
 public class ObservationBenchmark {
 
     SimpleMeterRegistry meterRegistry;
@@ -46,6 +49,8 @@ public class ObservationBenchmark {
 
     Timer timer;
 
+    ObservationConvention<Observation.Context> convention;
+
     @Setup
     public void setup() {
         this.meterRegistry = new SimpleMeterRegistry();
@@ -54,6 +59,25 @@ public void setup() {
         this.observationRegistry.observationConfig()
             .observationHandler(new DefaultMeterObservationHandler(meterRegistry));
         this.noopRegistry = ObservationRegistry.create();
+        this.convention = new ObservationConvention<Observation.Context>() {
+
+            @Override
+            public String getName() {
+                return "http.server.requests";
+            }
+
+            @Override
+            public KeyValues getLowCardinalityKeyValues(Observation.Context context) {
+                return KeyValues.of(KeyValue.of("exception", "none"), KeyValue.of("method", "GET"),
+                        KeyValue.of("outcome", "SUCCESS"), KeyValue.of("status", "200"),
+                        KeyValue.of("url", "/books/{bookId}"));
+            }
+
+            @Override
+            public boolean supportsContext(Observation.Context context) {
+                return true;
+            }
+        };
     }
 
     @TearDown
@@ -106,7 +130,11 @@ public long builtTimerAndLongTaskTimer() {
     @Benchmark
     public Observation observationWithoutThreadContention() {
         Observation observation = Observation.createNotStarted("test.obs", observationRegistry)
-            .lowCardinalityKeyValue("abc", "123")
+            .lowCardinalityKeyValue("exception", "none")
+            .lowCardinalityKeyValue("method", "GET")
+            .lowCardinalityKeyValue("outcome", "SUCCESS")
+            .lowCardinalityKeyValue("status", "200")
+            .lowCardinalityKeyValue("url", "/books/{bookId}")
             .start();
         observation.stop();
 
@@ -116,13 +144,34 @@ public Observation observationWithoutThreadContention() {
     @Benchmark
     public Observation observation() {
         Observation observation = Observation.createNotStarted("test.obs", observationRegistry)
-            .lowCardinalityKeyValue("abc", "123")
+            .lowCardinalityKeyValue("exception", "none")
+            .lowCardinalityKeyValue("method", "GET")
+            .lowCardinalityKeyValue("outcome", "SUCCESS")
+            .lowCardinalityKeyValue("status", "200")
+            .lowCardinalityKeyValue("url", "/books/{bookId}")
             .start();
         observation.stop();
 
         return observation;
     }
 
+    @Threads(1)
+    @Benchmark
+    public Observation observationConventionWithoutThreadContention() {
+        Observation observation = Observation.start(convention, observationRegistry);
+        observation.stop();
+
+        return observation;
+    }
+
+    @Benchmark
+    public Observation observationConvention() {
+        Observation observation = Observation.start(convention, observationRegistry);
+        observation.stop();
+
+        return observation;
+    }
+
     @Benchmark
     public ObservationOrTimerCompatibleInstrumentation<Observation.Context> observationOrTimer() {
         ObservationOrTimerCompatibleInstrumentation<Observation.Context> instrumentation = ObservationOrTimerCompatibleInstrumentation
diff --git a/micrometer-core/src/main/java/io/micrometer/core/instrument/AbstractTimerBuilder.java b/micrometer-core/src/main/java/io/micrometer/core/instrument/AbstractTimerBuilder.java
@@ -32,6 +32,15 @@
 @SuppressWarnings("unchecked")
 public abstract class AbstractTimerBuilder<B extends AbstractTimerBuilder<B>> {
 
+    /**
+     * Default {@link DistributionStatisticConfig} used with {@link Timer} if not
+     * overridden.
+     */
+    static final DistributionStatisticConfig DEFAULT_DISTRIBUTION_CONFIG = DistributionStatisticConfig.builder()
+        .minimumExpectedValue((double) Duration.ofMillis(1).toNanos())
+        .maximumExpectedValue((double) Duration.ofSeconds(30).toNanos())
+        .build();
+
     protected final String name;
 
     protected Tags tags = Tags.empty();
diff --git a/micrometer-core/src/main/java/io/micrometer/core/instrument/LongTaskTimer.java b/micrometer-core/src/main/java/io/micrometer/core/instrument/LongTaskTimer.java
@@ -287,6 +287,11 @@ abstract class Sample {
      */
     class Builder {
 
+        static final DistributionStatisticConfig DEFAULT_DISTRIBUTION_CONFIG = DistributionStatisticConfig.builder()
+            .minimumExpectedValue((double) Duration.ofMinutes(2).toNanos())
+            .maximumExpectedValue((double) Duration.ofHours(2).toNanos())
+            .build();
+
         private final String name;
 
         private Tags tags = Tags.empty();
diff --git a/micrometer-core/src/main/java/io/micrometer/core/instrument/MeterRegistry.java b/micrometer-core/src/main/java/io/micrometer/core/instrument/MeterRegistry.java
@@ -486,7 +486,8 @@ public DistributionSummary summary(String name, String... tags) {
      * @return A new or existing timer.
      */
     public Timer timer(String name, Iterable<Tag> tags) {
-        return Timer.builder(name).tags(tags).register(this);
+        return this.timer(new Meter.Id(name, Tags.of(tags), null, null, Meter.Type.TIMER),
+                AbstractTimerBuilder.DEFAULT_DISTRIBUTION_CONFIG, pauseDetector);
     }
 
     /**
@@ -1057,7 +1058,8 @@ public LongTaskTimer longTaskTimer(String name, String... tags) {
          * @return A new or existing long task timer.
          */
         public LongTaskTimer longTaskTimer(String name, Iterable<Tag> tags) {
-            return LongTaskTimer.builder(name).tags(tags).register(MeterRegistry.this);
+            return longTaskTimer(new Meter.Id(name, Tags.of(tags), null, null, Meter.Type.LONG_TASK_TIMER),
+                    LongTaskTimer.Builder.DEFAULT_DISTRIBUTION_CONFIG);
         }
 
         /**
diff --git a/micrometer-core/src/main/java/io/micrometer/core/instrument/observation/DefaultMeterObservationHandler.java b/micrometer-core/src/main/java/io/micrometer/core/instrument/observation/DefaultMeterObservationHandler.java
@@ -71,9 +71,8 @@ public DefaultMeterObservationHandler(MeterRegistry meterRegistry, IgnoredMeters
     @Override
     public void onStart(Observation.Context context) {
         if (shouldCreateLongTaskTimer) {
-            LongTaskTimer.Sample longTaskSample = LongTaskTimer.builder(context.getName() + ".active")
-                .tags(createTags(context))
-                .register(meterRegistry)
+            LongTaskTimer.Sample longTaskSample = meterRegistry.more()
+                .longTaskTimer(context.getName() + ".active", createTags(context))
                 .start();
             context.put(LongTaskTimer.Sample.class, longTaskSample);
         }
@@ -89,7 +88,7 @@ public void onStop(Observation.Context context) {
         List<Tag> tags = createTags(context);
         tags.add(Tag.of("error", getErrorValue(context)));
         Timer.Sample sample = context.getRequired(Timer.Sample.class);
-        sample.stop(Timer.builder(context.getName()).tags(tags).register(this.meterRegistry));
+        sample.stop(this.meterRegistry.timer(context.getName(), tags));
 
         if (shouldCreateLongTaskTimer) {
             LongTaskTimer.Sample longTaskSample = context.getRequired(LongTaskTimer.Sample.class);
