gradle-build-performance

Gradle Build Performance

When to Use

• Build times are slow (clean or incremental)
• Investigating build performance regressions
• Analyzing Gradle Build Scans
• Identifying configuration vs execution bottlenecks
• Optimizing CI/CD build times
• Enabling Gradle Configuration Cache
• Reducing unnecessary recompilation
• Debugging kapt/KSP annotation processing

Example Prompts

• "My builds are slow, how can I speed them up?"
• "How do I analyze a Gradle build scan?"
• "Why is configuration taking so long?"
• "Why does my project always recompile everything?"
• "How do I enable configuration cache?"
• "Why is kapt so slow?"

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Workflow

1. Measure Baseline — Clean build + incremental build times
2. Generate Build Scan — ./gradlew assembleDebug --scan
3. Identify Phase — Configuration? Execution? Dependency resolution?
4. Apply ONE optimization — Don't batch changes
5. Measure Improvement — Compare against baseline
6. Verify in Build Scan — Visual confirmation

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Quick Diagnostics

Generate Build Scan

./gradlew assembleDebug --scan

Profile Build Locally

./gradlew assembleDebug --profile
# Opens report in build/reports/profile/

Build Timing Summary

./gradlew assembleDebug --info | grep -E "^\:.*"
# Or view in Android Studio: Build > Analyze APK Build

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Build Phases

Phase	What Happens	Common Issues
Initialization	settings.gradle.kts evaluated	Too many include() statements
Configuration	All build.gradle.kts files evaluated	Expensive plugins, eager task creation
Execution	Tasks run based on inputs/outputs	Cache misses, non-incremental tasks

Identify the Bottleneck

Build scan → Performance → Build timeline

• Long configuration phase: Focus on plugin and buildscript optimization
• Long execution phase: Focus on task caching and parallelization
• Dependency resolution slow: Focus on repository configuration