GROOVY-10307: Groovy 6 - Improve invokedynamic performance with optimized caching

[jamesfredley]

Summary

Based on #2374, but applied to master(Groovy 6) instead of GROOVY_4_0_X

This PR improves invokedynamic performance reported in GROOVY-10307. The optimization reduces the performance impact of metaclass changes on call sites by replacing the global SwitchPoint invalidation mechanism with targeted per-call-site cache invalidation.

Problem

When any metaclass changes in Groovy, the global SwitchPoint is invalidated, causing all invokedynamic call sites across the entire application to fall back and re-link. This creates significant overhead in applications that frequently modify metaclasses (e.g., Grails applications with dynamic finders, runtime mixins, etc.).

Solution

This PR implements a more targeted invalidation strategy:

1. Disable global SwitchPoint guard by default - The SwitchPoint.guardWithTest() wrapper is now optional and disabled by default. This prevents mass invalidation of all call sites when any metaclass changes.

2. Track all call sites via WeakReference set - All CacheableCallSite instances are registered in a concurrent set using weak references, allowing targeted invalidation without preventing garbage collection.

3. Add clearCache() method to CacheableCallSite - When a metaclass changes, we can now clear the LRU cache and reset the fallback count on specific call sites rather than invalidating everything.

4. Targeted invalidation on metaclass change - invalidateSwitchPoints() now iterates through registered call sites, clearing caches and resetting targets as needed.

Changes

CacheableCallSite.java

• Added clearCache() method to clear LRU cache and reset fallback count

IndyInterface.java

• Added ALL_CALL_SITES WeakReference set to track all call sites
• Added registerCallSite(CacheableCallSite) method
• Modified invalidateSwitchPoints() to clear caches on all registered call sites
• Register call sites during bootstrap

Selector.java

• Added INDY_SWITCHPOINT_GUARD system property flag (default: false)
• Made the SwitchPoint guard conditional based on the flag

JarJarTask.groovy (unrelated build fix)

• Changed @InputFiles @Classpath to @Input on untouchedFiles field
• Fixes Windows build issue where glob patterns containing * were treated as literal file paths

Configuration

The SwitchPoint guard behavior can be controlled via system property:

# Use new targeted invalidation (default)
java -jar myapp.jar

# Revert to old global SwitchPoint behavior
java -Dgroovy.indy.switchpoint.guard=true -jar myapp.jar

Benchmark Results

Tested using a dedicated benchmark suite measuring metaclass invalidation impact: https://github.com/jamesfredley/groovy-indy-performance

Complete Benchmark Comparison (3-Run Averages)

Test Date: February 4, 2026
Test Machine: Windows 11, 20 cores, 4GB max heap
Java Version: 17.0.18 (Amazon Corretto)

Versions Tested

Version	Description
4.0.30	Groovy 4.0.30 from Maven Central (baseline)
6-snapshot	Groovy 6.0.0-SNAPSHOT clean master (no optimizations)
6-snapshot-opt	Groovy 6.0.0-SNAPSHOT with this PRs optimizations

Optimizations Applied in 6-snapshot-opt

1. Disabled global SwitchPoint guard - INDY_SWITCHPOINT_GUARD defaults to false
2. Call site registry - Track all call sites via WeakReference set
3. Cache invalidation - Clear individual call site caches on metaclass change
4. Target reset - Reset call site targets to default on invalidation

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🎯 KEY METRIC: Metaclass Invalidation Stress Test

This test measures the performance impact when metaclass changes occur during execution.
Lower ratio = better (less performance degradation from metaclass changes).

Metric	4.0.30	6-snapshot	6-snapshot-opt
Run 1	72.66x	83.16x	67.33x
Run 2	103.63x	77.54x	76.90x
Run 3	107.92x	103.71x	71.26x
Average	94.74x	88.14x	71.83x
Baseline (no changes)	5.61 ms	5.84 ms	6.02 ms
With metaclass changes	515.11 ms	505.83 ms	431.28 ms

Key Finding

6-snapshot-opt reduces metaclass invalidation impact by:

• 19% vs 6-snapshot (71.83x vs 88.14x)
• 24% vs 4.0.30 (71.83x vs 94.74x)

---

Comprehensive Benchmark Suite (3-Run Averages)

Benchmark	4.0.30	6-snapshot	6-snapshot-opt
Loop Benchmarks
Loop: each + toString	31.72 ms	49.23 ms	50.37 ms
Loop: collect	52.12 ms	75.74 ms	75.80 ms
Loop: findAll	113.37 ms	146.15 ms	147.52 ms
Method Invocation
Method: simple instance	8.81 ms	27.53 ms	27.74 ms
Method: with params	10.33 ms	27.49 ms	29.32 ms
Method: static	7.54 ms	26.49 ms	26.56 ms
Method: polymorphic	1.86 s	2.03 s	1.86 s
Closures
Closure: creation + call	24.93 ms	34.87 ms	34.27 ms
Closure: reused	20.59 ms	27.70 ms	27.85 ms
Closure: nested	39.16 ms	37.46 ms	38.27 ms
Closure: curried	159.16 ms	191.60 ms	192.33 ms
Properties
Property: read/write	19.62 ms	71.62 ms	73.83 ms
Collections
Collection: each	108.84 ms	127.27 ms	128.85 ms
Collection: collect	119.86 ms	138.99 ms	138.79 ms
Collection: inject	133.79 ms	153.63 ms	155.63 ms
GStrings
GString: simple	101.42 ms	118.48 ms	118.47 ms
GString: multi-value	114.82 ms	130.68 ms	129.68 ms
Call Site Performance
Monomorphic call site	124.68 ms	117.98 ms	117.21 ms
Polymorphic call site	3.73 s	3.79 s	3.56 s

---

Closure Benchmark Suite (3-Run Averages)

Benchmark	4.0.30	6-snapshot	6-snapshot-opt
Simple closure creation	29.71 ms	14.86 ms	16.20 ms
Closure reuse	19.25 ms	10.08 ms	10.99 ms
Multi-param closure	38.58 ms	19.25 ms	21.48 ms
Closure with capture	19.60 ms	7.48 ms	7.66 ms
Closure modify capture	12.87 ms	4.73 ms	4.29 ms
Closure delegation	27.94 ms	27.97 ms	25.87 ms
Nested closures	58.24 ms	26.16 ms	25.84 ms
Curried closure	294.13 ms	337.07 ms	332.51 ms
Closure composition	59.20 ms	70.86 ms	73.05 ms
Closure spread	2.05 s	2.66 s	2.66 s
Closure.call()	22.32 ms	8.56 ms	8.99 ms
Closure trampoline	53.48 ms	60.26 ms	59.67 ms

---

Loop Benchmark Suite (3-Run Averages)

Benchmark	4.0.30	6-snapshot	6-snapshot-opt
Original: each + toString	45.54 ms	48.94 ms	49.51 ms
Simple: each only	39.93 ms	47.65 ms	48.95 ms
Closure call	19.54 ms	2.58 ms	2.74 ms
Method call	5.32 ms	6.02 ms	5.33 ms
Nested loops	74.47 ms	79.96 ms	79.68 ms
Loop with collect	88.51 ms	106.90 ms	105.39 ms
Loop with findAll	202.83 ms	233.18 ms	232.28 ms

---

Method Invocation Benchmark Suite (3-Run Averages)

Benchmark	4.0.30	6-snapshot	6-snapshot-opt
Simple instance method	7.69 ms	6.17 ms	5.75 ms
Method with parameters	7.89 ms	7.85 ms	8.08 ms
Method with object param	10.89 ms	10.61 ms	10.64 ms
Static method	3.20 ms	3.42 ms	3.48 ms
Static method with params	7.87 ms	8.16 ms	7.67 ms
Interface method	3.24 ms	3.81 ms	3.69 ms
Dynamic typed calls	3.26 ms	3.26 ms	3.31 ms
Property access	21.50 ms	N/A	N/A
GString method	192.53 ms	N/A	N/A

---

Raw Data: Individual Run Results

Metaclass Invalidation Ratios

Run	4.0.30	6-snapshot	6-snapshot-opt
1	72.66x	83.16x	67.33x
2	103.63x	77.54x	76.90x
3	107.92x	103.71x	71.26x

With Metaclass Changes (ms)

Run	4.0.30	6-snapshot	6-snapshot-opt
1	517.31	515.21	430.71
2	508.25	504.47	429.30
3	519.77	497.80	433.84

Baseline (No Metaclass Changes) (ms)

Run	4.0.30	6-snapshot	6-snapshot-opt
1	7.12	6.20	6.40
2	4.90	6.51	5.58
3	4.82	4.80	6.09

Existing Test Coverage:

• MetaClassRegistryTest.groovy - loads IndyInterface explicitly and tests metaclass change events
• CallSiteTest.groovy - Tests call site updates after metaclass changes

Related

• JIRA: https://issues.apache.org/jira/browse/GROOVY-10307
• Original PR: GROOVY-10307: Improve invokedynamic performance with optimized caching #2374
• Test project: https://github.com/jamesfredley/groovy-indy-performance
• Since this PR is against Groovy 6, the Grails 7 test project will not run

[codecov-commenter]

Codecov Report

❌ Patch coverage is 80.00000% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 68.3418%. Comparing base (a7bebd3) to head (ddf0121).

Files with missing lines	Patch %	Lines
...java/org/codehaus/groovy/vmplugin/v8/Selector.java	25.0000%	2 Missing and 1 partial ⚠️
...org/codehaus/groovy/vmplugin/v8/IndyInterface.java	86.6667%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@                Coverage Diff                 @@
##               master      #2377        +/-   ##
==================================================
+ Coverage     68.3341%   68.3418%   +0.0077%     
- Complexity      30319      30327         +8     
==================================================
  Files            1382       1382                
  Lines          116087     116109        +22     
  Branches        20464      20467         +3     
==================================================
+ Hits            79327      79351        +24     
+ Misses          30261      30259         -2     
  Partials         6499       6499                

Files with missing lines	Coverage Δ
...codehaus/groovy/vmplugin/v8/CacheableCallSite.java	80.2817% <100.0000%> (+3.3586%)	⬆️
...org/codehaus/groovy/vmplugin/v8/IndyInterface.java	88.0795% <86.6667%> (+0.4882%)	⬆️
...java/org/codehaus/groovy/vmplugin/v8/Selector.java	81.1741% <25.0000%> (-0.3300%)	⬇️

... and 4 files with indirect coverage changes

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[Copilot]

Pull request overview

This pull request improves invokedynamic performance in Groovy 6 by replacing the global SwitchPoint invalidation mechanism with targeted per-call-site cache invalidation. When metaclasses change in Groovy, instead of invalidating ALL call sites across the application, only the cached method handles at each call site are cleared, significantly reducing overhead in applications that frequently modify metaclasses.

Changes:

• Introduced a call site registry using WeakReferences to track all active call sites for targeted invalidation
• Made the global SwitchPoint guard optional (disabled by default) via the groovy.indy.switchpoint.guard system property
• Added cache clearing mechanism to CacheableCallSite for metaclass change handling
• Fixed a Windows build issue in JarJarTask by correcting the annotation for glob pattern strings

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
src/main/java/org/codehaus/groovy/vmplugin/v8/Selector.java	Made global SwitchPoint guard conditional via INDY_SWITCHPOINT_GUARD property (disabled by default)
src/main/java/org/codehaus/groovy/vmplugin/v8/IndyInterface.java	Added WeakReference-based call site registry and targeted cache invalidation logic
src/main/java/org/codehaus/groovy/vmplugin/v8/CacheableCallSite.java	Added clearCache() method to clear LRU cache and reset fallback count on metaclass changes
build-logic/src/main/groovy/org/apache/groovy/gradle/JarJarTask.groovy	Fixed annotation from @InputFiles @classpath to @input for glob pattern strings

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