From 01ae43b9a0d84f78a6df80045943a9cbf195c645 Mon Sep 17 00:00:00 2001 From: Douglas Q Hawkins Date: Sat, 25 Jul 2026 10:27:15 -0400 Subject: [PATCH] Add TraceCreationBenchmark; production-shape front-half span benchmarks Add TraceCreationBenchmark (full-trace front-half: a web-request arm and a parameterized fan-out arm, children created under an active root scope) as a reference others can key core-optimization gains and regressions off of. Production-shape both front-half benchmarks' fork config (dd.service/env/version + 6 global dd.tags) so mergedTracerTags is a realistically-sized shared bundle; a bare tracer leaves it near-empty and hides any win that scales with tags-per-span. Flag SpanCreationBenchmark's historical table as a pre-config (bare-tracer) baseline, not comparable going forward. Co-Authored-By: Claude Opus 4.8 --- .../trace/core/SpanCreationBenchmark.java | 21 +- .../trace/core/TraceCreationBenchmark.java | 215 ++++++++++++++++++ 2 files changed, 235 insertions(+), 1 deletion(-) create mode 100644 dd-trace-core/src/jmh/java/datadog/trace/core/TraceCreationBenchmark.java diff --git a/dd-trace-core/src/jmh/java/datadog/trace/core/SpanCreationBenchmark.java b/dd-trace-core/src/jmh/java/datadog/trace/core/SpanCreationBenchmark.java index d288463faad..8f7c0428f8d 100644 --- a/dd-trace-core/src/jmh/java/datadog/trace/core/SpanCreationBenchmark.java +++ b/dd-trace-core/src/jmh/java/datadog/trace/core/SpanCreationBenchmark.java @@ -56,6 +56,14 @@ * drop is the TagMap 1.0 shared-Entry default flip; the ~1.61 drop is the interceptor/links * cluster. Net 1.53 → 1.64 is -20% to -31% per arm. * + *

Note — baseline reset. The table below was measured on a bare ({@code + * CoreTracer.builder().build()}) tracer. As of this commit the fork is production-shaped ({@code + * dd.service}/{@code dd.env}/{@code dd.version} + 6 global {@code dd.tags}), which enlarges {@code + * mergedTracerTags} — the trace-level bundle every span merges — so tag-scaling wins are actually + * exercised. That raises absolute B/op across all arms, so the numbers below are a pre-config + * baseline, not comparable to runs on this branch onward; re-baseline going forward rather + * than stitching new points onto this curve. + * * 

  * ver    bareStart bareBuild webServer viaBuilder jdbcClient
  * 1.53      1330.7    1331.1    2058.7     2434.7     1821.3
@@ -98,7 +106,18 @@
 @BenchmarkMode(Mode.Throughput)
 @Threads(8)
 @OutputTimeUnit(MICROSECONDS)
-@Fork(value = 3, jvmArgsAppend = "-DTEST_LOG_LEVEL=warn")
+@Fork(
+    value = 3,
+    jvmArgsAppend = {
+      "-DTEST_LOG_LEVEL=warn",
+      // Production-shaped tracer config so mergedTracerTags is a realistically-sized shared bundle
+      // (env + 6 global DD_TAGS + runtime-id/language) — the trace-level tags every span merges.
+      // A bare tracer leaves it near-empty, hiding any win that scales with tags-per-span.
+      "-Ddd.service=petclinic",
+      "-Ddd.env=staging",
+      "-Ddd.version=1.2.3",
+      "-Ddd.tags=team:apm,dc:us1,cluster:prod-1,owner:tracing,tier:backend,region:us-east-1"
+    })
 public class SpanCreationBenchmark {
   private static final String INSTRUMENTATION_NAME = "bench";
   private static final String SERVER_OPERATION_NAME = "servlet.request";
diff --git a/dd-trace-core/src/jmh/java/datadog/trace/core/TraceCreationBenchmark.java b/dd-trace-core/src/jmh/java/datadog/trace/core/TraceCreationBenchmark.java
new file mode 100644
index 00000000000..e9f2ca77937
--- /dev/null
+++ b/dd-trace-core/src/jmh/java/datadog/trace/core/TraceCreationBenchmark.java
@@ -0,0 +1,215 @@
+package datadog.trace.core;
+
+import static java.util.concurrent.TimeUnit.MICROSECONDS;
+
+import datadog.trace.bootstrap.instrumentation.api.AgentScope;
+import datadog.trace.bootstrap.instrumentation.api.AgentSpan;
+import datadog.trace.bootstrap.instrumentation.api.Tags;
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Measurement;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+import org.openjdk.jmh.annotations.Param;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.Setup;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.annotations.TearDown;
+import org.openjdk.jmh.annotations.Threads;
+import org.openjdk.jmh.annotations.Warmup;
+import org.openjdk.jmh.infra.Blackhole;
+
+/**
+ * Front-half allocation/throughput for creating a whole trace (a local-root span plus its
+ * children), as opposed to the single-span {@link SpanCreationBenchmark}. One op = one complete
+ * trace: root started, activated, children created-and-finished under it, then root finished.
+ *
+ * 
Purpose — a reference others can key off when implementing core optimizations:
+ *
+ * 
    
+ *   
  • Win visibility. Optimizations that touch per-span cost (trace-level tag sharing,
+ *       context propagation, pending-trace bookkeeping) accrue per span, so a trace of
+ *       {@code 1+childCount} spans surfaces the per-trace payoff a single-span bench cannot.
+ *   
  • Regression guard. A documented baseline (below) lets a later change to core show up
+ *       as a delta — "did this addition move overhead?" — rather than passing silently.
+ * 

+ *
+ * 
Isolation: children are created under an active root scope, so this exercises the real
+ * parent-context propagation and trace-tag inheritance a single-span bench cannot reach. A no-op
+ * {@link DropWriter} drops finished traces (handing them to a {@link Blackhole} so the JIT can't
+ * dead-code the finish()-triggered write) so only application-thread (front-half) allocation lands
+ * in the {@code -prof gc} number, with no serialization or agent I/O.
+ *
+ * 
The tracer is production-shaped via {@code @Fork} jvmArgs (service/env/version + global {@code
+ * dd.tags}) so {@code mergedTracerTags} is a realistically-sized shared bundle — the same config as
+ * {@link SpanCreationBenchmark}, keeping numbers comparable across the two.
+ *
+ * 
Read {@code gc.alloc.rate.norm} (B/op, deterministic) as the primary signal; throughput is
+ * directional-only (laptop thermals + per-fork inlining bimodality).
+ *
+ * 
Historical results (populate from a committed run on the branch this file lives on;
+ * matches the {@link SpanCreationBenchmark} header convention):
+ *
+ * 
+ *   date        commit    arm                         alloc B/op      thrpt ops/us
+ *   ----        ------    ---                         ----------      ------------
+ *   (TBD — fill from first green run on this branch)
+ * 

+ */
+@State(Scope.Benchmark)
+@Warmup(iterations = 5)
+@Measurement(iterations = 5)
+@BenchmarkMode(Mode.Throughput)
+@Threads(8)
+@OutputTimeUnit(MICROSECONDS)
+@Fork(
+    value = 3,
+    jvmArgsAppend = {
+      "-DTEST_LOG_LEVEL=warn",
+      // Production-shaped tracer config so mergedTracerTags is a realistically-sized shared bundle
+      // (env + 6 global DD_TAGS + runtime-id/language) — the trace-level tags every span merges.
+      // Same config as SpanCreationBenchmark so the two benchmarks' numbers stay comparable.
+      "-Ddd.service=petclinic",
+      "-Ddd.env=staging",
+      "-Ddd.version=1.2.3",
+      "-Ddd.tags=team:apm,dc:us1,cluster:prod-1,owner:tracing,tier:backend,region:us-east-1"
+    })
+public class TraceCreationBenchmark {
+  private static final String INSTRUMENTATION_NAME = "bench";
+  private static final String SERVER_OPERATION_NAME = "servlet.request";
+  private static final String JDBC_OPERATION_NAME = "database.query";
+  private static final String HTTP_CLIENT_OPERATION_NAME = "http.request";
+  private static final String INTERNAL_OPERATION_NAME = "internal.work";
+
+  // Web-server (local root) tag shape — mirrors SpanCreationBenchmark.webServerSpan.
+  private static final String COMPONENT_VALUE = "tomcat-server";
+  private static final String HTTP_METHOD_VALUE = "GET";
+  private static final String HTTP_ROUTE_VALUE = "/owners/{ownerId}";
+  private static final String HTTP_URL_VALUE = "http://localhost:8080/owners/42";
+  private static final int HTTP_STATUS_VALUE = 100; // in Integer cache; boxing does not allocate
+  private static final int PEER_PORT_VALUE = 80;
+
+  // JDBC-client child tag shape — mirrors SpanCreationBenchmark.jdbcClientSpan.
+  private static final String DB_COMPONENT_VALUE = "java-jdbc-statement";
+  private static final String DB_TYPE_VALUE = "postgresql";
+  private static final String DB_INSTANCE_VALUE = "petclinic";
+  private static final String DB_USER_VALUE = "app";
+  private static final String DB_OPERATION_VALUE = "SELECT";
+  private static final String DB_STATEMENT_VALUE = "SELECT * FROM owners WHERE id = ?";
+  private static final String DB_PEER_HOSTNAME_VALUE = "db.internal";
+  private static final int DB_PEER_PORT_VALUE = 90; // in Integer cache; boxing does not allocate
+
+  // HTTP-client child tag shape.
+  private static final String HTTP_CLIENT_COMPONENT_VALUE = "apache-httpclient";
+  private static final String HTTP_CLIENT_URL_VALUE = "http://billing.internal/charge";
+  private static final String HTTP_CLIENT_PEER_HOSTNAME_VALUE = "billing.internal";
+  private static final int HTTP_CLIENT_PEER_PORT_VALUE = 90; // in Integer cache; no alloc
+
+  // Internal child tag shape (a light span, few tags).
+  private static final String INTERNAL_COMPONENT_VALUE = "spring-scheduler";
+
+  /** Fan-out width for {@link #fanoutTrace()} — root + this many jdbc-shaped children. */
+  @Param({"1", "5", "10"})
+  int childCount;
+
+  CoreTracer tracer;
+
+  @Setup
+  public void setup(Blackhole blackhole) {
+    this.tracer = CoreTracer.builder().writer(new DropWriter(blackhole)).build();
+  }
+
+  @TearDown
+  public void tearDown() {
+    this.tracer.close();
+  }
+
+  /**
+   * Fixed, realistic web request: a server local root with a JDBC-client, an HTTP-client, and an
+   * internal child. One headline number that mirrors the shape of a real request. Not affected by
+   * {@link #childCount} (JMH still runs it once per param value — read any single row).
+   */
+  @Benchmark
+  public void webRequestTrace() {
+    AgentSpan root = tracer.buildSpan(INSTRUMENTATION_NAME, SERVER_OPERATION_NAME).start();
+    root.setTag(Tags.COMPONENT, COMPONENT_VALUE);
+    root.setTag(Tags.SPAN_KIND, Tags.SPAN_KIND_SERVER);
+    root.setTag(Tags.HTTP_METHOD, HTTP_METHOD_VALUE);
+    root.setTag(Tags.HTTP_ROUTE, HTTP_ROUTE_VALUE);
+    root.setTag(Tags.HTTP_URL, HTTP_URL_VALUE);
+    root.setTag(Tags.HTTP_STATUS, HTTP_STATUS_VALUE);
+    root.setTag(Tags.PEER_PORT, PEER_PORT_VALUE);
+
+    AgentScope scope = tracer.activateSpan(root);
+    try {
+      jdbcChild();
+      httpClientChild();
+      internalChild();
+    } finally {
+      scope.close();
+    }
+    root.finish();
+  }
+
+  /**
+   * Fan-out trace: a server local root with {@link #childCount} JDBC-shaped children. The scaling
+   * axis — per-trace cost as span count grows exposes how per-span optimizations compound.
+   */
+  @Benchmark
+  public void fanoutTrace() {
+    AgentSpan root = tracer.buildSpan(INSTRUMENTATION_NAME, SERVER_OPERATION_NAME).start();
+    root.setTag(Tags.COMPONENT, COMPONENT_VALUE);
+    root.setTag(Tags.SPAN_KIND, Tags.SPAN_KIND_SERVER);
+    root.setTag(Tags.HTTP_METHOD, HTTP_METHOD_VALUE);
+    root.setTag(Tags.HTTP_ROUTE, HTTP_ROUTE_VALUE);
+    root.setTag(Tags.HTTP_URL, HTTP_URL_VALUE);
+    root.setTag(Tags.HTTP_STATUS, HTTP_STATUS_VALUE);
+    root.setTag(Tags.PEER_PORT, PEER_PORT_VALUE);
+
+    AgentScope scope = tracer.activateSpan(root);
+    try {
+      for (int i = 0; i < childCount; i++) {
+        jdbcChild();
+      }
+    } finally {
+      scope.close();
+    }
+    root.finish();
+  }
+
+  /** A JDBC-client child of the currently-active span. */
+  private void jdbcChild() {
+    AgentSpan span = tracer.buildSpan(INSTRUMENTATION_NAME, JDBC_OPERATION_NAME).start();
+    span.setTag(Tags.COMPONENT, DB_COMPONENT_VALUE);
+    span.setTag(Tags.SPAN_KIND, Tags.SPAN_KIND_CLIENT);
+    span.setTag(Tags.DB_TYPE, DB_TYPE_VALUE);
+    span.setTag(Tags.DB_INSTANCE, DB_INSTANCE_VALUE);
+    span.setTag(Tags.DB_USER, DB_USER_VALUE);
+    span.setTag(Tags.DB_OPERATION, DB_OPERATION_VALUE);
+    span.setTag(Tags.DB_STATEMENT, DB_STATEMENT_VALUE);
+    span.setTag(Tags.PEER_HOSTNAME, DB_PEER_HOSTNAME_VALUE);
+    span.setTag(Tags.PEER_PORT, DB_PEER_PORT_VALUE);
+    span.finish();
+  }
+
+  /** An HTTP-client child of the currently-active span. */
+  private void httpClientChild() {
+    AgentSpan span = tracer.buildSpan(INSTRUMENTATION_NAME, HTTP_CLIENT_OPERATION_NAME).start();
+    span.setTag(Tags.COMPONENT, HTTP_CLIENT_COMPONENT_VALUE);
+    span.setTag(Tags.SPAN_KIND, Tags.SPAN_KIND_CLIENT);
+    span.setTag(Tags.HTTP_METHOD, HTTP_METHOD_VALUE);
+    span.setTag(Tags.HTTP_URL, HTTP_CLIENT_URL_VALUE);
+    span.setTag(Tags.HTTP_STATUS, HTTP_STATUS_VALUE);
+    span.setTag(Tags.PEER_HOSTNAME, HTTP_CLIENT_PEER_HOSTNAME_VALUE);
+    span.setTag(Tags.PEER_PORT, HTTP_CLIENT_PEER_PORT_VALUE);
+    span.finish();
+  }
+
+  /** A light internal child of the currently-active span. */
+  private void internalChild() {
+    AgentSpan span = tracer.buildSpan(INSTRUMENTATION_NAME, INTERNAL_OPERATION_NAME).start();
+    span.setTag(Tags.COMPONENT, INTERNAL_COMPONENT_VALUE);
+    span.finish();
+  }
+}