From 4da3e71626367e760a01c63ba48a012c186aaf3d Mon Sep 17 00:00:00 2001
From: Jack Berg <34418638+jack-berg@users.noreply.github.com>
Date: Mon, 20 Apr 2026 09:26:15 -0500
Subject: [PATCH 1/2] Tune benchmark params to reduce variance

---
 .../io/opentelemetry/sdk/LogRecordBenchmark.java     | 12 ++++++------
 .../io/opentelemetry/sdk/MetricRecordBenchmark.java  | 12 ++++++------
 .../io/opentelemetry/sdk/SpanRecordBenchmark.java    | 12 ++++++------
 3 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/sdk/all/src/jmh/java/io/opentelemetry/sdk/LogRecordBenchmark.java b/sdk/all/src/jmh/java/io/opentelemetry/sdk/LogRecordBenchmark.java
index ae54e627221..5355874209a 100644
--- a/sdk/all/src/jmh/java/io/opentelemetry/sdk/LogRecordBenchmark.java
+++ b/sdk/all/src/jmh/java/io/opentelemetry/sdk/LogRecordBenchmark.java
@@ -112,9 +112,9 @@ public void tearDown() {
   @Benchmark
   @Group("threads1")
   @GroupThreads(1)
-  @Fork(1)
-  @Warmup(iterations = 5, time = 1)
-  @Measurement(iterations = 5, time = 1)
+  @Fork(3)
+  @Warmup(iterations = 3, time = 1)
+  @Measurement(iterations = 10, time = 1)
   @OperationsPerInvocation(RECORDS_PER_INVOCATION)
   public void record_SingleThread(BenchmarkState benchmarkState) {
     record(benchmarkState);
@@ -123,9 +123,9 @@ public void record_SingleThread(BenchmarkState benchmarkState) {
   @Benchmark
   @Group("threads" + MAX_THREADS)
   @GroupThreads(MAX_THREADS)
-  @Fork(1)
-  @Warmup(iterations = 5, time = 1)
-  @Measurement(iterations = 5, time = 1)
+  @Fork(3)
+  @Warmup(iterations = 3, time = 1)
+  @Measurement(iterations = 10, time = 1)
   @OperationsPerInvocation(RECORDS_PER_INVOCATION)
   public void record_MultipleThreads(BenchmarkState benchmarkState) {
     record(benchmarkState);
diff --git a/sdk/all/src/jmh/java/io/opentelemetry/sdk/MetricRecordBenchmark.java b/sdk/all/src/jmh/java/io/opentelemetry/sdk/MetricRecordBenchmark.java
index 669127b9eb7..2d821cfb90a 100644
--- a/sdk/all/src/jmh/java/io/opentelemetry/sdk/MetricRecordBenchmark.java
+++ b/sdk/all/src/jmh/java/io/opentelemetry/sdk/MetricRecordBenchmark.java
@@ -187,9 +187,9 @@ public void tearDown() {
   @Benchmark
   @Group("threads1")
   @GroupThreads(1)
-  @Fork(1)
-  @Warmup(iterations = 5, time = 1)
-  @Measurement(iterations = 5, time = 1)
+  @Fork(3)
+  @Warmup(iterations = 3, time = 1)
+  @Measurement(iterations = 10, time = 1)
   @OperationsPerInvocation(RECORDS_PER_INVOCATION)
   public void record_SingleThread(BenchmarkState benchmarkState) {
     record(benchmarkState);
@@ -198,9 +198,9 @@ public void record_SingleThread(BenchmarkState benchmarkState) {
   @Benchmark
   @Group("threads" + MAX_THREADS)
   @GroupThreads(MAX_THREADS)
-  @Fork(1)
-  @Warmup(iterations = 5, time = 1)
-  @Measurement(iterations = 5, time = 1)
+  @Fork(3)
+  @Warmup(iterations = 3, time = 1)
+  @Measurement(iterations = 10, time = 1)
   @OperationsPerInvocation(RECORDS_PER_INVOCATION)
   public void record_MultipleThreads(BenchmarkState benchmarkState) {
     record(benchmarkState);
diff --git a/sdk/all/src/jmh/java/io/opentelemetry/sdk/SpanRecordBenchmark.java b/sdk/all/src/jmh/java/io/opentelemetry/sdk/SpanRecordBenchmark.java
index 69bc3198001..24aae90060e 100644
--- a/sdk/all/src/jmh/java/io/opentelemetry/sdk/SpanRecordBenchmark.java
+++ b/sdk/all/src/jmh/java/io/opentelemetry/sdk/SpanRecordBenchmark.java
@@ -123,9 +123,9 @@ public void tearDown() {
   @Benchmark
   @Group("threads1")
   @GroupThreads(1)
-  @Fork(1)
-  @Warmup(iterations = 5, time = 1)
-  @Measurement(iterations = 5, time = 1)
+  @Fork(3)
+  @Warmup(iterations = 3, time = 1)
+  @Measurement(iterations = 10, time = 1)
   @OperationsPerInvocation(RECORDS_PER_INVOCATION)
   public void record_SingleThread(BenchmarkState benchmarkState) {
     record(benchmarkState);
@@ -134,9 +134,9 @@ public void record_SingleThread(BenchmarkState benchmarkState) {
   @Benchmark
   @Group("threads" + MAX_THREADS)
   @GroupThreads(MAX_THREADS)
-  @Fork(1)
-  @Warmup(iterations = 5, time = 1)
-  @Measurement(iterations = 5, time = 1)
+  @Fork(3)
+  @Warmup(iterations = 3, time = 1)
+  @Measurement(iterations = 10, time = 1)
   @OperationsPerInvocation(RECORDS_PER_INVOCATION)
   public void record_MultipleThreads(BenchmarkState benchmarkState) {
     record(benchmarkState);

From 2d48b130870a60733796de0f52d164d2dd4f515f Mon Sep 17 00:00:00 2001
From: Jack Berg <34418638+jack-berg@users.noreply.github.com>
Date: Tue, 21 Apr 2026 15:19:20 -0500
Subject: [PATCH 2/2] cardinality 100 -> 128 for improved JIT modulo

---
 .../jmh/java/io/opentelemetry/sdk/MetricRecordBenchmark.java    | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sdk/all/src/jmh/java/io/opentelemetry/sdk/MetricRecordBenchmark.java b/sdk/all/src/jmh/java/io/opentelemetry/sdk/MetricRecordBenchmark.java
index 2d821cfb90a..a417fd72b3b 100644
--- a/sdk/all/src/jmh/java/io/opentelemetry/sdk/MetricRecordBenchmark.java
+++ b/sdk/all/src/jmh/java/io/opentelemetry/sdk/MetricRecordBenchmark.java
@@ -96,7 +96,7 @@ public static class BenchmarkState {
 
     @Param AggregationTemporality aggregationTemporality;
 
-    @Param({"1", "100"})
+    @Param({"1", "128"})
     int cardinality;
 
     // The following parameters are excluded from the benchmark to reduce combinatorial explosion