Add VarHandle note to AtomicsBenchmark Javadoc

dougqh · claude · dougqh · commit bb784c0bb102 · 2026-06-22T19:59:59.000-04:00
VarHandle (Java 9+) is the modern replacement for AtomicIntegerFieldUpdater
and would likely close the incrementAndGet performance gap. Not usable here
because internal-api targets Java 8.

Co-Authored-By: Claude Sonnet 4.6 &lt;noreply@anthropic.com&gt;
diff --git a/internal-api/src/jmh/java/datadog/trace/util/AtomicsBenchmark.java b/internal-api/src/jmh/java/datadog/trace/util/AtomicsBenchmark.java
@@ -27,6 +27,11 @@
  *
  * AtomicFieldUpdater supports {@code int}, {@code long}, and reference types.
  *
+ * <p><b>Future:</b> {@code VarHandle} (Java 9+) is the modern replacement for
+ * AtomicIntegerFieldUpdater. It avoids the reflective field-access overhead, which should close
+ * the incrementAndGet gap with AtomicInteger while retaining the construction allocation advantage.
+ * Not available here because internal-api targets Java 8.
+ *
  * <code> Java 17 - MacBook M1 - 8 threads
  * Benchmark                                                                Mode  Cnt           Score           Error   Units
  * AtomicsBenchmark.atomicFieldUpdater_construction                        thrpt    6  2215272588.708 ±  88556141.052   ops/s

Original file line number	Diff line number	Diff line change
`@@ -27,6 +27,11 @@`
`27`	`27`	`*`
`28`	`28`	`* AtomicFieldUpdater supports {@code int}, {@code long}, and reference types.`
`29`	`29`	`*`
	`30`	`+ * <p><b>Future:</b> {@code VarHandle} (Java 9+) is the modern replacement for`
	`31`	`+ * AtomicIntegerFieldUpdater. It avoids the reflective field-access overhead, which should close`
	`32`	`+ * the incrementAndGet gap with AtomicInteger while retaining the construction allocation advantage.`
	`33`	`+ * Not available here because internal-api targets Java 8.`
	`34`	`+ *`
`30`	`35`	`* <code> Java 17 - MacBook M1 - 8 threads`
`31`	`36`	`* Benchmark Mode Cnt Score Error Units`
`32`	`37`	`* AtomicsBenchmark.atomicFieldUpdater_construction thrpt 6 2215272588.708 ± 88556141.052 ops/s`