Benchmark Advisor Skill

This skill analyzes your code changes and recommends specific Criterion benchmarks to run.

When to Use

This skill automatically activates when:

• You've made changes to performance-critical code
• You're preparing to commit performance-related work
• You want to verify your changes don't introduce regressions

How It Works

1. Detects Changed Files: Analyzes git diff to see which files you've modified
2. Maps to Benchmarks: Uses pattern matching to identify relevant benchmarks
3. Provides Recommendations: Suggests specific cargo bench commands with explanations

Usage

Simply ask:

• "What benchmarks should I run?"
• "Which benchmarks are affected by my changes?"
• "Suggest benchmarks for my current work"

Skill Logic

# 1. Detect changed files
CHANGED_FILES=$(git diff --name-only HEAD)

# 2. Load mapping configuration
# See mapping.toml for file-to-benchmark mappings

# 3. Match changed files to benchmarks
# Example mappings:
#   src/cache/**/*.rs → cargo bench --bench cache
#   src/config/**/*.rs → cargo bench --bench config
#   src/main.rs → cargo bench (full suite - affects startup time)

# 4. Generate recommendation with explanation

Example Interaction

User: "What benchmarks should I run?"

Claude: "I analyzed your changes and found modifications to:

• src/cache/manifest.rs
• src/cache/lru.rs

Recommended benchmarks:

cargo bench --bench cache

Why: Changes to cache implementation files can affect cache operation performance (get_model, add_model, remove_model, lru_eviction).

You can also run the full suite if you want comprehensive validation:

cargo bench
```"

## Mapping Configuration

The skill uses `mapping.toml` to define file patterns and their corresponding benchmarks:

```toml
# Cache-related files
[[mapping]]
pattern = "src/cache/**/*.rs"
benchmark = "cargo bench --bench cache"
reason = "Cache implementation changes can affect cache operation performance"

# Config-related files
[[mapping]]
pattern = "src/config/**/*.rs"
benchmark = "cargo bench --bench config"
reason = "Config loading and merging performance may be impacted"

# Main entry point
[[mapping]]
pattern = "src/main.rs"
benchmark = "cargo bench"
reason = "Main entry point affects startup time - run full suite"

Output Format

Concise: Lists changed files, recommended command, and brief explanation

No false positives: Only suggests benchmarks for performance-critical changes

Actionable: Provides exact commands to copy/paste