GROOVY-10307: Add targeted JMH benchmarks for SwitchPoint invalidation

subprojects/performance/src/jmh/groovy/org/apache/groovy/perf/grails/CallSiteInvalidationBench.groovy

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+/*
+ *  Licensed to the Apache Software Foundation (ASF) under one
+ *  or more contributor license agreements.  See the NOTICE file
+ *  distributed with this work for additional information
+ *  regarding copyright ownership.  The ASF licenses this file
+ *  to you 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
+ *
+ *    http://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 org.apache.groovy.perf.grails
+
+import groovy.lang.ExpandoMetaClass
+import groovy.lang.GroovySystem
+
+import org.openjdk.jmh.annotations.*
+import org.openjdk.jmh.infra.Blackhole
+
+import java.util.concurrent.TimeUnit
+
+/**
+ * SwitchPoint invalidation overhead for Grails-like metaclass change patterns.
+ *
+ * @see <a href="https://issues.apache.org/jira/browse/GROOVY-10307">GROOVY-10307</a>
+ */
+@Warmup(iterations = 3, time = 2, timeUnit = TimeUnit.SECONDS)
+@Measurement(iterations = 5, time = 2, timeUnit = TimeUnit.SECONDS)
+@Fork(2)
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.MILLISECONDS)
+@State(Scope.Thread)
+class CallSiteInvalidationBench {
+    static final int ITERATIONS = 100_000
+
+    static class HotTarget {
+        int value = 42
+        int compute() { value * 2 }
+        String describe() { "v=$value" }
+    }
+
+    static class HotTargetB {
+        int count = 10
+        int getCount() { count }
+    }
+
+    static class HotTargetC {
+        List items = [1, 2, 3]
+        int itemCount() { items.size() }
+    }
+
+    static class ColdType {
+        String label = "cold"
+    }
+
+    HotTarget hotTarget
+    HotTargetB hotTargetB
+    HotTargetC hotTargetC
+    List<Integer> sampleList
+
+    @Setup(Level.Iteration)
+    void setup() {
+        GroovySystem.metaClassRegistry.removeMetaClass(HotTarget)
+        GroovySystem.metaClassRegistry.removeMetaClass(HotTargetB)
+        GroovySystem.metaClassRegistry.removeMetaClass(HotTargetC)
+        GroovySystem.metaClassRegistry.removeMetaClass(ColdType)
+        hotTarget = new HotTarget()
+        hotTargetB = new HotTargetB()
+        hotTargetC = new HotTargetC()
+        sampleList = [1, 2, 3, 4, 5]
+    }
+
+    /** Single method call in tight loop, no invalidation. */
+    @Benchmark
+    void baselineHotLoop(Blackhole bh) {
+        int sum = 0
+        for (int i = 0; i < ITERATIONS; i++) {
+            sum += hotTarget.compute()
+        }
+        bh.consume(sum)
+    }
+
+    /** list.size() in tight loop, no invalidation. */
+    @Benchmark
+    void baselineListSize(Blackhole bh) {
+        int sum = 0
+        for (int i = 0; i < ITERATIONS; i++) {
+            sum += sampleList.size()
+        }
+        bh.consume(sum)
+    }
+
+    /** Cross-type invalidation every 1000 calls. */
+    @Benchmark
+    void crossTypeInvalidationEvery1000(Blackhole bh) {
+        int sum = 0
+        for (int i = 0; i < ITERATIONS; i++) {
+            sum += hotTarget.compute()
+            if (i % 1000 == 0) {
+                ColdType.metaClass."dynamic${i % 5}" = { -> i }
+            }
+        }
+        bh.consume(sum)
+    }
+
+    /** Cross-type invalidation every 100 calls. */
+    @Benchmark
+    void crossTypeInvalidationEvery100(Blackhole bh) {
+        int sum = 0
+        for (int i = 0; i < ITERATIONS; i++) {
+            sum += hotTarget.compute()
+            if (i % 100 == 0) {
+                ColdType.metaClass."dynamic${i % 5}" = { -> i }
+            }
+        }
+        bh.consume(sum)
+    }
+
+    /** Cross-type invalidation every 10000 calls. */
+    @Benchmark
+    void crossTypeInvalidationEvery10000(Blackhole bh) {
+        int sum = 0
+        for (int i = 0; i < ITERATIONS; i++) {
+            sum += hotTarget.compute()
+            if (i % 10000 == 0) {
+                ColdType.metaClass."dynamic${i % 5}" = { -> i }
+            }
+        }
+        bh.consume(sum)
+    }
+
+    /** list.size() with cross-type invalidation every 1000 calls. */
+    @Benchmark
+    void listSizeWithCrossTypeInvalidation(Blackhole bh) {
+        int sum = 0
+        for (int i = 0; i < ITERATIONS; i++) {
+            sum += sampleList.size()
+            if (i % 1000 == 0) {
+                ColdType.metaClass."dynamic${i % 5}" = { -> i }
+            }
+        }
+        bh.consume(sum)
+    }
+
+    /** Same-type invalidation every 1000 calls. */
+    @Benchmark
+    void sameTypeInvalidationEvery1000(Blackhole bh) {
+        int sum = 0
+        for (int i = 0; i < ITERATIONS; i++) {
+            sum += hotTarget.compute()
+            if (i % 1000 == 0) {
+                HotTarget.metaClass."dynamic${i % 5}" = { -> i }
+            }
+        }
+        bh.consume(sum)
+    }
+
+    /** Five method calls across three types, no invalidation. */
+    @Benchmark
+    void baselineMultipleCallSites(Blackhole bh) {
+        int sum = 0
+        for (int i = 0; i < ITERATIONS; i++) {
+            sum += hotTarget.compute()
+            sum += hotTarget.describe().length()
+            sum += hotTargetB.getCount()
+            sum += hotTargetC.itemCount()
+            sum += sampleList.size()
+        }
+        bh.consume(sum)
+    }
+
+    /** Five call sites with cross-type invalidation every 1000 calls. */
+    @Benchmark
+    void multipleCallSitesWithInvalidation(Blackhole bh) {
+        int sum = 0
+        for (int i = 0; i < ITERATIONS; i++) {
+            sum += hotTarget.compute()
+            sum += hotTarget.describe().length()
+            sum += hotTargetB.getCount()
+            sum += hotTargetC.itemCount()
+            sum += sampleList.size()
+            if (i % 1000 == 0) {
+                ColdType.metaClass."dynamic${i % 5}" = { -> i }
+            }
+        }
+        bh.consume(sum)
+    }
+
+    /** 100 metaclass changes then steady-state method calls. */
+    @Benchmark
+    void burstThenSteadyState(Blackhole bh) {
+        // Phase 1: Burst of metaclass changes (framework startup)
+        for (int i = 0; i < 100; i++) {
+            ColdType.metaClass."startup${i % 20}" = { -> i }
+        }
+
+        // Phase 2: Steady-state method calls (request handling)
+        int sum = 0
+        for (int i = 0; i < ITERATIONS; i++) {
+            sum += hotTarget.compute()
+            sum += hotTargetB.getCount()
+            sum += sampleList.size()
+        }
+        bh.consume(sum)
+    }
+
+    /** Steady-state method calls with no preceding burst. */
+    @Benchmark
+    void baselineSteadyStateNoBurst(Blackhole bh) {
+        int sum = 0
+        for (int i = 0; i < ITERATIONS; i++) {
+            sum += hotTarget.compute()
+            sum += hotTargetB.getCount()
+            sum += sampleList.size()
+        }
+        bh.consume(sum)
+    }
+}