Support for ExponentialHistogram in OTLP Registry

benchmarks/benchmarks-core/build.gradle

@@ -5,6 +5,7 @@ plugins {
 dependencies {
     jmh project(':micrometer-core')
     jmh project(':micrometer-registry-prometheus')
+    jmh project(':micrometer-registry-otlp')
 
     jmh 'io.dropwizard.metrics5:metrics-core:latest.release'
     jmh 'io.prometheus:simpleclient_common:latest.release'

benchmarks/benchmarks-core/src/jmh/java/io/micrometer/benchmark/compare/CompareOTLPHistograms.java

@@ -0,0 +1,337 @@
+/*
+ * Copyright 2023 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.compare;
+
+import java.util.Iterator;
+import java.util.Random;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import org.openjdk.jmh.annotations.*;
+import org.openjdk.jmh.infra.Blackhole;
+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;
+//CHECKSTYLE:OFF
+import com.google.common.collect.Iterators;
+////CHECKSTYLE:ON
+import io.micrometer.common.lang.Nullable;
+import io.micrometer.core.instrument.Clock;
+import io.micrometer.core.instrument.DistributionSummary;
+import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.Timer;
+import io.micrometer.registry.otlp.AggregationTemporality;
+import io.micrometer.registry.otlp.HistogramFlavour;
+import io.micrometer.registry.otlp.OtlpConfig;
+import io.micrometer.registry.otlp.OtlpMeterRegistry;
+
+/**
+ * @author Lenin Jaganathan
+ */
+@Fork(1)
+@Measurement(iterations = 2)
+@Warmup(iterations = 2)
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.NANOSECONDS)
+@Threads(16)
+public class CompareOTLPHistograms {
+
+    @State(Scope.Thread)
+    public static class Data {
+
+        Iterator<Long> dataIterator;
+
+        @Setup(Level.Iteration)
+        public void setup() {
+            final Random r = new Random(1234567891L);
+            dataIterator = Iterators.cycle(Stream.generate(() -> {
+                long randomNumber;
+                do {
+                    randomNumber = Math.round(Math.exp(2.0 + r.nextGaussian()));
+                }
+                while (randomNumber < 1 || randomNumber > 60000);
+                return randomNumber;
+            }).limit(1048576).collect(Collectors.toList()));
+        }
+
+    }
+
+    @State(Scope.Benchmark)
+    public static class DistributionsWithoutHistogramCumulative {
+
+        MeterRegistry registry;
+
+        Timer timer;
+
+        DistributionSummary distributionSummary;
+
+        @Setup(Level.Iteration)
+        public void setup() {
+            registry = new OtlpMeterRegistry();
+            distributionSummary = DistributionSummary.builder("ds").register(registry);
+            timer = Timer.builder("timer").register(registry);
+        }
+
+        @TearDown(Level.Iteration)
+        public void tearDown(Blackhole hole) {
+            hole.consume(distributionSummary.takeSnapshot());
+        }
+
+    }
+
+    @State(Scope.Benchmark)
+    public static class DistributionsWithoutHistogramDelta {
+
+        OtlpConfig otlpConfig = new OtlpConfig() {
+
+            @Override
+            public AggregationTemporality aggregationTemporality() {
+                return AggregationTemporality.DELTA;
+            }
+
+            @Nullable
+            @Override
+            public String get(final String key) {
+                return null;
+            }
+        };
+
+        MeterRegistry registry;
+
+        Timer timer;
+
+        DistributionSummary distributionSummary;
+
+        @Setup(Level.Iteration)
+        public void setup() {
+            registry = new OtlpMeterRegistry(otlpConfig, Clock.SYSTEM);
+            distributionSummary = DistributionSummary.builder("ds").register(registry);
+            timer = Timer.builder("timer").register(registry);
+        }
+
+        @TearDown(Level.Iteration)
+        public void tearDown(Blackhole hole) {
+            hole.consume(distributionSummary.takeSnapshot());
+        }
+
+    }
+
+    @State(Scope.Benchmark)
+    public static class ExplicitBucketHistogramCumulative {
+
+        MeterRegistry registry;
+
+        Timer timer;
+
+        DistributionSummary distributionSummary;
+
+        @Setup(Level.Iteration)
+        public void setup() {
+            registry = new OtlpMeterRegistry();
+            distributionSummary = DistributionSummary.builder("ds").publishPercentileHistogram().register(registry);
+            timer = Timer.builder("timer").publishPercentileHistogram().register(registry);
+        }
+
+        @TearDown(Level.Iteration)
+        public void tearDown(Blackhole hole) {
+            hole.consume(distributionSummary.takeSnapshot());
+        }
+
+    }
+
+    @State(Scope.Benchmark)
+    public static class ExplicitBucketHistogramDelta {
+
+        OtlpConfig otlpConfig = new OtlpConfig() {
+
+            @Override
+            public AggregationTemporality aggregationTemporality() {
+                return AggregationTemporality.DELTA;
+            }
+
+            @Nullable
+            @Override
+            public String get(final String key) {
+                return null;
+            }
+        };
+
+        MeterRegistry registry;
+
+        Timer timer;
+
+        DistributionSummary distributionSummary;
+
+        @Setup(Level.Iteration)
+        public void setup() {
+            registry = new OtlpMeterRegistry(otlpConfig, Clock.SYSTEM);
+            distributionSummary = DistributionSummary.builder("ds").publishPercentileHistogram().register(registry);
+            timer = Timer.builder("timer").publishPercentileHistogram().register(registry);
+        }
+
+        @TearDown(Level.Iteration)
+        public void tearDown(Blackhole hole) {
+            hole.consume(distributionSummary.takeSnapshot());
+        }
+
+    }
+
+    @State(Scope.Benchmark)
+    public static class ExponentialHistogramCumulative {
+
+        MeterRegistry registry;
+
+        OtlpConfig otlpConfig = new OtlpConfig() {
+            @Override
+            public HistogramFlavour histogramFlavour() {
+                return HistogramFlavour.BASE2_EXPONENTIAL_BUCKET_HISTOGRAM;
+            }
+
+            @Nullable
+            @Override
+            public String get(final String key) {
+                return null;
+            }
+        };
+
+        Timer timer;
+
+        DistributionSummary distributionSummary;
+
+        @Setup(Level.Iteration)
+        public void setup() {
+            registry = new OtlpMeterRegistry(otlpConfig, Clock.SYSTEM);
+            distributionSummary = DistributionSummary.builder("ds").publishPercentileHistogram().register(registry);
+            timer = Timer.builder("timer").publishPercentileHistogram().register(registry);
+        }
+
+        @TearDown(Level.Iteration)
+        public void tearDown(Blackhole hole) {
+            hole.consume(distributionSummary.takeSnapshot());
+        }
+
+    }
+
+    @State(Scope.Benchmark)
+    public static class ExponentialHistogramDelta {
+
+        MeterRegistry registry;
+
+        OtlpConfig otlpConfig = new OtlpConfig() {
+
+            @Override
+            public AggregationTemporality aggregationTemporality() {
+                return AggregationTemporality.DELTA;
+            }
+
+            @Override
+            public HistogramFlavour histogramFlavour() {
+                return HistogramFlavour.BASE2_EXPONENTIAL_BUCKET_HISTOGRAM;
+            }
+
+            @Nullable
+            @Override
+            public String get(final String key) {
+                return null;
+            }
+        };
+
+        Timer timer;
+
+        DistributionSummary distributionSummary;
+
+        @Setup(Level.Iteration)
+        public void setup() {
+            registry = new OtlpMeterRegistry(otlpConfig, Clock.SYSTEM);
+            distributionSummary = DistributionSummary.builder("ds").publishPercentileHistogram().register(registry);
+            timer = Timer.builder("timer").publishPercentileHistogram().register(registry);
+        }
+
+        @TearDown(Level.Iteration)
+        public void tearDown(Blackhole hole) {
+            hole.consume(distributionSummary.takeSnapshot());
+        }
+
+    }
+
+    @Benchmark
+    public void otlpCumulativeDs(DistributionsWithoutHistogramCumulative state, Data data) {
+        state.distributionSummary.record(data.dataIterator.next());
+    }
+
+    @Benchmark
+    public void otlpDeltaDs(DistributionsWithoutHistogramDelta state, Data data) {
+        state.distributionSummary.record(data.dataIterator.next());
+    }
+
+    @Benchmark
+    public void otlpCumulativeExplicitBucketHistogramDs(ExplicitBucketHistogramCumulative state, Data data) {
+        state.distributionSummary.record(data.dataIterator.next());
+    }
+
+    @Benchmark
+    public void otlpDeltaExplicitBucketHistogramDs(ExplicitBucketHistogramDelta state, Data data) {
+        state.distributionSummary.record(data.dataIterator.next());
+    }
+
+    @Benchmark
+    public void oltpCumulativeExponentialHistogramDs(ExponentialHistogramCumulative state, Data data) {
+        state.distributionSummary.record(data.dataIterator.next());
+    }
+
+    @Benchmark
+    public void oltpDeltaExponentialHistogramDs(ExponentialHistogramDelta state, Data data) {
+        state.distributionSummary.record(data.dataIterator.next());
+    }
+
+    @Benchmark
+    public void otlpCumulativeTimer(DistributionsWithoutHistogramCumulative state, Data data) {
+        state.timer.record(data.dataIterator.next(), TimeUnit.MILLISECONDS);
+    }
+
+    @Benchmark
+    public void otlpDeltaTimer(DistributionsWithoutHistogramDelta state, Data data) {
+        state.timer.record(data.dataIterator.next(), TimeUnit.MILLISECONDS);
+    }
+
+    @Benchmark
+    public void otlpCumulativeExplicitBucketHistogramTimer(ExplicitBucketHistogramCumulative state, Data data) {
+        state.timer.record(data.dataIterator.next(), TimeUnit.MILLISECONDS);
+    }
+
+    @Benchmark
+    public void otlpDeltaExplicitBucketHistogramTimer(ExplicitBucketHistogramDelta state, Data data) {
+        state.timer.record(data.dataIterator.next(), TimeUnit.MILLISECONDS);
+    }
+
+    @Benchmark
+    public void oltpCumulativeExponentialHistogramTimer(ExponentialHistogramCumulative state, Data data) {
+        state.timer.record(data.dataIterator.next(), TimeUnit.MILLISECONDS);
+    }
+
+    @Benchmark
+    public void oltpDeltaExponentialHistogramTimer(ExponentialHistogramDelta state, Data data) {
+        state.timer.record(data.dataIterator.next(), TimeUnit.MILLISECONDS);
+    }
+
+    public static void main(String[] args) throws RunnerException {
+        Options opt = new OptionsBuilder().include(CompareOTLPHistograms.class.getSimpleName()).build();
+        new Runner(opt).run();
+    }
+
+}

implementations/micrometer-registry-otlp/src/main/java/io/micrometer/registry/otlp/HistogramFlavour.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2023 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.registry.otlp;
+
+/**
+ * Histogram Flavour to be used while recording distributions,
+ *
+ * @see <a href=
+ * "https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/sdk_exporters/otlp.md#additional-configuration">OTLP
+ * Configuration</a>
+ * @author Lenin Jaganathan
+ * @since 1.12.0
+ */
+public enum HistogramFlavour {
+
+    EXPLICIT_BUCKET_HISTOGRAM, BASE2_EXPONENTIAL_BUCKET_HISTOGRAM;
+
+    /**
+     * Converts a string to {@link HistogramFlavour} by using a case-insensitive matching.
+     */
+    public static HistogramFlavour fromString(final String histogramPreference) {
+        if (BASE2_EXPONENTIAL_BUCKET_HISTOGRAM.name().equalsIgnoreCase(histogramPreference)) {
+            return BASE2_EXPONENTIAL_BUCKET_HISTOGRAM;
+        }
+        return EXPLICIT_BUCKET_HISTOGRAM;
+    }
+
+}