FIx for BSP benchmark aux counters (exportedSpans/droppedSpans) always reporting zero

sdk/trace/src/jmh/java/io/opentelemetry/sdk/trace/export/BatchSpanProcessorCpuBenchmark.java

@@ -28,6 +28,7 @@
 import org.openjdk.jmh.annotations.TearDown;
 import org.openjdk.jmh.annotations.Threads;
 import org.openjdk.jmh.annotations.Warmup;
+import org.openjdk.jmh.infra.BenchmarkParams;
 
 /*
  * Run this along with a profiler to measure the CPU usage of BatchSpanProcessor's exporter thread.
@@ -47,7 +48,8 @@ public static class BenchmarkState {
     private long droppedSpans;
 
     @Setup(Level.Iteration)
-    public final void setup() {
+    public final void setup(BenchmarkParams params) {
+      numThreads = params.getThreads();
       metricReader = InMemoryMetricReader.create();
       MeterProvider meterProvider =
           SdkMeterProvider.builder().registerMetricReader(metricReader).build();
@@ -110,7 +112,6 @@ private static void doWork(BenchmarkState benchmarkState) {
   @OutputTimeUnit(TimeUnit.SECONDS)
   public void export_01Thread(
       BenchmarkState benchmarkState, @SuppressWarnings("unused") ThreadState threadState) {
-    benchmarkState.numThreads = 1;
     doWork(benchmarkState);
   }
 
@@ -123,7 +124,6 @@ public void export_01Thread(
   @OutputTimeUnit(TimeUnit.SECONDS)
   public void export_02Thread(
       BenchmarkState benchmarkState, @SuppressWarnings("unused") ThreadState threadState) {
-    benchmarkState.numThreads = 2;
     doWork(benchmarkState);
   }
 
@@ -136,7 +136,6 @@ public void export_02Thread(
   @OutputTimeUnit(TimeUnit.SECONDS)
   public void export_05Thread(
       BenchmarkState benchmarkState, @SuppressWarnings("unused") ThreadState threadState) {
-    benchmarkState.numThreads = 5;
     doWork(benchmarkState);
   }
 
@@ -149,7 +148,6 @@ public void export_05Thread(
   @OutputTimeUnit(TimeUnit.SECONDS)
   public void export_10Thread(
       BenchmarkState benchmarkState, @SuppressWarnings("unused") ThreadState threadState) {
-    benchmarkState.numThreads = 10;
     doWork(benchmarkState);
   }
 
@@ -162,7 +160,6 @@ public void export_10Thread(
   @OutputTimeUnit(TimeUnit.SECONDS)
   public void export_20Thread(
       BenchmarkState benchmarkState, @SuppressWarnings("unused") ThreadState threadState) {
-    benchmarkState.numThreads = 20;
     doWork(benchmarkState);
   }
 }

sdk/trace/src/jmh/java/io/opentelemetry/sdk/trace/export/BatchSpanProcessorDroppedSpansBenchmark.java

@@ -24,6 +24,7 @@
 import org.openjdk.jmh.annotations.TearDown;
 import org.openjdk.jmh.annotations.Threads;
 import org.openjdk.jmh.annotations.Warmup;
+import org.openjdk.jmh.infra.BenchmarkParams;
 
 public class BatchSpanProcessorDroppedSpansBenchmark {
 
@@ -36,9 +37,12 @@ public static class BenchmarkState {
     private long exportedSpans;
     private long droppedSpans;
     private int numThreads;
+    private int numIterations;
 
     @Setup(Level.Iteration)
-    public final void setup() {
+    public final void setup(BenchmarkParams params) {
+      numThreads = params.getThreads();
+      numIterations = params.getMeasurement().getCount();
       metricReader = InMemoryMetricReader.create();
       MeterProvider meterProvider =
           SdkMeterProvider.builder().registerMetricReader(metricReader).build();
@@ -52,7 +56,7 @@ public final void setup() {
     public final void recordMetrics() {
       BatchSpanProcessorMetrics metrics =
           new BatchSpanProcessorMetrics(metricReader.collectAllMetrics(), numThreads);
-      dropRatio = metrics.dropRatio();
+      dropRatio = metrics.dropRatio(numIterations);
       exportedSpans = metrics.exportedSpans();
       droppedSpans = metrics.droppedSpans();
     }
@@ -64,7 +68,7 @@ public final void tearDown() {
   }
 
   @State(Scope.Thread)
-  @AuxCounters(AuxCounters.Type.OPERATIONS)
+  @AuxCounters(AuxCounters.Type.EVENTS)
   public static class ThreadState {
     BenchmarkState benchmarkState;
 
@@ -95,7 +99,6 @@ public long droppedSpans() {
   @BenchmarkMode(Mode.Throughput)
   public void export(
       BenchmarkState benchmarkState, @SuppressWarnings("unused") ThreadState threadState) {
-    benchmarkState.numThreads = 5;
     benchmarkState.processor.onEnd(
         (ReadableSpan) benchmarkState.tracer.spanBuilder("span").startSpan());
   }

sdk/trace/src/jmh/java/io/opentelemetry/sdk/trace/export/BatchSpanProcessorMetrics.java

@@ -5,12 +5,13 @@
 
 package io.opentelemetry.sdk.trace.export;
 
-import static io.opentelemetry.api.common.AttributeKey.stringKey;
+import static io.opentelemetry.api.common.AttributeKey.booleanKey;
 
 import io.opentelemetry.sdk.metrics.data.LongPointData;
 import io.opentelemetry.sdk.metrics.data.MetricData;
 import java.util.Collection;
 import java.util.OptionalLong;
+import org.openjdk.jmh.annotations.AuxCounters;
 
 public class BatchSpanProcessorMetrics {
   private final Collection<MetricData> allMetrics;
@@ -21,13 +22,26 @@ public BatchSpanProcessorMetrics(Collection<MetricData> allMetrics, int numThrea
     this.numThreads = numThreads;
   }
 
-  public double dropRatio() {
+  /**
+   * Returns the share of dropped spans as a value in {@code [0, 1]}.
+   *
+   * <p>Only meaningful for benchmarks whose {@link AuxCounters} use {@link
+   * AuxCounters.Type#EVENTS}: JMH emits a {@code ScalarResult} with {@code AggregationPolicy.SUM},
+   * which sums the aux counters across the {@code numThreads} thread-local {@code @State} instances
+   * and the {@code numIterations} measurement iterations. The raw {@code dropped / (exported +
+   * dropped)} is therefore inflated by {@code numThreads * numIterations}, and both factors are
+   * divided back out here so the value reported by JMH equals the per-iteration drop ratio.
+   *
+   * <p>For {@link AuxCounters.Type#OPERATIONS} JMH emits a {@code ThroughputResult} (rate per unit
+   * time) aggregated as a mean across iterations, so this method does not apply — the drop rate is
+   * read directly from {@link #droppedSpans()} and the ratio, if needed, is computed from the two
+   * rates.
+   */
+  public double dropRatio(int numIterations) {
     long exported = getMetric(false);
     long dropped = getMetric(true);
     long total = exported + dropped;
-    // Due to peculiarities of JMH reporting we have to divide this by the number of the
-    // concurrent threads running the actual benchmark.
-    return total == 0 ? 0 : (double) dropped / total / numThreads;
+    return total == 0 ? 0.0 : (double) dropped / total / numThreads / numIterations;
   }
 
   public long exportedSpans() {
@@ -39,14 +53,17 @@ public long droppedSpans() {
   }
 
   private long getMetric(boolean dropped) {
-    String labelValue = String.valueOf(dropped);
     OptionalLong value =
         allMetrics.stream()
             .filter(metricData -> metricData.getName().equals("processedSpans"))
             .filter(metricData -> !metricData.isEmpty())
             .map(metricData -> metricData.getLongSumData().getPoints())
             .flatMap(Collection::stream)
-            .filter(point -> labelValue.equals(point.getAttributes().get(stringKey("dropped"))))
+            .filter(
+                point -> {
+                  Boolean attrDropped = point.getAttributes().get(booleanKey("dropped"));
+                  return attrDropped != null && attrDropped == dropped;
+                })
             .mapToLong(LongPointData::getValue)
             .findFirst();
     return value.isPresent() ? value.getAsLong() : 0;

sdk/trace/src/jmh/java/io/opentelemetry/sdk/trace/export/BatchSpanProcessorMultiThreadBenchmark.java

@@ -27,6 +27,7 @@
 import org.openjdk.jmh.annotations.TearDown;
 import org.openjdk.jmh.annotations.Threads;
 import org.openjdk.jmh.annotations.Warmup;
+import org.openjdk.jmh.infra.BenchmarkParams;
 
 @State(Scope.Benchmark)
 public class BatchSpanProcessorMultiThreadBenchmark {
@@ -37,15 +38,19 @@ public static class BenchmarkState {
     private BatchSpanProcessor processor;
     private Tracer tracer;
     private int numThreads = 1;
+    private int numIterations = 1;
 
     @Param({"0"})
     private int delayMs;
 
+    private double dropRatio;
     private long exportedSpans;
     private long droppedSpans;
 
     @Setup(Level.Iteration)
-    public final void setup() {
+    public final void setup(BenchmarkParams params) {
+      numThreads = params.getThreads();
+      numIterations = params.getMeasurement().getCount();
       collector = InMemoryMetricReader.create();
       MeterProvider meterProvider =
           SdkMeterProvider.builder().registerMetricReader(collector).build();
@@ -59,14 +64,15 @@ public final void setup() {
     public final void recordMetrics() {
       BatchSpanProcessorMetrics metrics =
           new BatchSpanProcessorMetrics(collector.collectAllMetrics(), numThreads);
+      dropRatio = metrics.dropRatio(numIterations);
       exportedSpans = metrics.exportedSpans();
       droppedSpans = metrics.droppedSpans();
       processor.shutdown().join(10, TimeUnit.SECONDS);
     }
   }
 
   @State(Scope.Thread)
-  @AuxCounters(AuxCounters.Type.OPERATIONS)
+  @AuxCounters(AuxCounters.Type.EVENTS)
   public static class ThreadState {
     BenchmarkState benchmarkState;
 
@@ -75,6 +81,10 @@ public final void recordMetrics(BenchmarkState benchmarkState) {
       this.benchmarkState = benchmarkState;
     }
 
+    public double dropRatio() {
+      return benchmarkState.dropRatio;
+    }
+
     public long exportedSpans() {
       return benchmarkState.exportedSpans;
     }
@@ -93,7 +103,6 @@ public long droppedSpans() {
   @OutputTimeUnit(TimeUnit.SECONDS)
   public void export_01Thread(
       BenchmarkState benchmarkState, @SuppressWarnings("unused") ThreadState threadState) {
-    benchmarkState.numThreads = 1;
     benchmarkState.processor.onEnd(
         (ReadableSpan) benchmarkState.tracer.spanBuilder("span").startSpan());
   }
@@ -107,7 +116,6 @@ public void export_01Thread(
   @OutputTimeUnit(TimeUnit.SECONDS)
   public void export_02Thread(
       BenchmarkState benchmarkState, @SuppressWarnings("unused") ThreadState threadState) {
-    benchmarkState.numThreads = 2;
     benchmarkState.processor.onEnd(
         (ReadableSpan) benchmarkState.tracer.spanBuilder("span").startSpan());
   }
@@ -121,7 +129,6 @@ public void export_02Thread(
   @OutputTimeUnit(TimeUnit.SECONDS)
   public void export_05Thread(
       BenchmarkState benchmarkState, @SuppressWarnings("unused") ThreadState threadState) {
-    benchmarkState.numThreads = 5;
     benchmarkState.processor.onEnd(
         (ReadableSpan) benchmarkState.tracer.spanBuilder("span").startSpan());
   }
@@ -135,7 +142,6 @@ public void export_05Thread(
   @OutputTimeUnit(TimeUnit.SECONDS)
   public void export_10Thread(
       BenchmarkState benchmarkState, @SuppressWarnings("unused") ThreadState threadState) {
-    benchmarkState.numThreads = 10;
     benchmarkState.processor.onEnd(
         (ReadableSpan) benchmarkState.tracer.spanBuilder("span").startSpan());
   }
@@ -149,7 +155,6 @@ public void export_10Thread(
   @OutputTimeUnit(TimeUnit.SECONDS)
   public void export_20Thread(
       BenchmarkState benchmarkState, @SuppressWarnings("unused") ThreadState threadState) {
-    benchmarkState.numThreads = 20;
     benchmarkState.processor.onEnd(
         (ReadableSpan) benchmarkState.tracer.spanBuilder("span").startSpan());
   }