Benchmark Common Skill

This skill provides comprehensive benchmarking standards for performance comparison. Designed to compare multiple implementations in a single benchmark file.

When to Use

• Compare different implementations (e.g., RingBuffer vs LinkedListBuffer)
• Measure performance of Common packages
• Validate optimization effectiveness
• Find performance bottlenecks

Quality Standards

Workflow (Strict 3-Step Process)

Step 1: Benchmark Design

Identify:

1. Implementations to compare: List all types/approaches
2. Operations to benchmark: Core operations (Read, Write, etc.)
3. Data sizes: Small (64B), Medium (1KB), Large (1MB)
4. Setup requirements: Pre-allocation, warm-up needs

Output Format:

## Benchmark Design: [comparison name]

### Implementations
- [Implementation 1]: Description
- [Implementation 2]: Description

### Operations
| Operation | Description | Why benchmark? |
|-----------|-------------|----------------|
| Write | Append data | Core operation |
| Read | Consume data | Core operation |

### Data Sizes
- Small: 64 bytes (cache-friendly)
- Medium: 1KB (typical payload)
- Large: 1MB (stress test)

STOP and wait for user approval.

Step 2: Benchmark Case Design

Create benchmark matrix:

Considerations:

• Same data for all implementations
• Pre-allocate to avoid setup cost in measurement
• Reset between iterations
• Report memory allocations

STOP and wait for user approval.

Step 3: Benchmark Code Implementation

Follow these Go benchmarking standards:

File Structure

benchmark_comparison_test.go
├── // Data generators
│   var smallData = make([]byte, 64)
│   var mediumData = make([]byte, 1024)
│   var largeData = make([]byte, 1<<20)
│
├── // Comparison benchmarks (grouped by operation)
│   func BenchmarkWrite(b *testing.B)
│   ├── b.Run("RingBuffer/64B", ...)
│   ├── b.Run("RingBuffer/1KB", ...)
│   ├── b.Run("LinkedList/64B", ...)
│   └── b.Run("LinkedList/1KB", ...)
│
├── func BenchmarkRead(b *testing.B)
│   ├── b.Run("RingBuffer/64B", ...)
│   └── ...

Code Patterns

Comparison Benchmark (Grouped by Operation):

func BenchmarkWrite(b *testing.B) {
    sizes := []struct {
        name string
        data []byte
    }{
        {"64B", make([]byte, 64)},
        {"1KB", make([]byte, 1024)},
        {"1MB", make([]byte, 1<<20)},
    }

    for _, size := range sizes {
        // RingBuffer
        b.Run("RingBuffer/"+size.name, func(b *testing.B) {
            buf := NewRing(len(size.data) * 2)
            b.ResetTimer()
            b.ReportAllocs()
            for i := 0; i < b.N; i++ {
                buf.Write(size.data)
                buf.Reset()
            }
        })

        // LinkedListBuffer
        b.Run("LinkedList/"+size.name, func(b *testing.B) {
            buf := &LinkedListBuffer{}
            b.ResetTimer()
            b.ReportAllocs()
            for i := 0; i < b.N; i++ {
                buf.PushBack(size.data)
                buf.Reset()
            }
        })
    }
}

Read After Write Pattern:

func BenchmarkRead(b *testing.B) {
    data := make([]byte, 1024)
    readBuf := make([]byte, 1024)

    b.Run("RingBuffer", func(b *testing.B) {
        buf := NewRing(2048)
        b.ResetTimer()
        b.ReportAllocs()
        for i := 0; i < b.N; i++ {
            buf.Write(data)
            buf.Read(readBuf)
        }
    })

    b.Run("LinkedList", func(b *testing.B) {
        buf := &LinkedListBuffer{}
        b.ResetTimer()
        b.ReportAllocs()
        for i := 0; i < b.N; i++ {
            buf.PushBack(data)
            buf.Read(readBuf)
        }
    })
}

Memory-Heavy Benchmark:

func BenchmarkMemory(b *testing.B) {
    b.Run("RingBuffer/Grow", func(b *testing.B) {
        b.ReportAllocs()
        for i := 0; i < b.N; i++ {
            buf := NewRing(64)
            for j := 0; j < 1000; j++ {
                buf.Write(make([]byte, 100))
            }
        }
    })
}

Running Benchmarks

# Run all benchmarks
go test -bench=. -benchmem

# Run specific comparison
go test -bench=BenchmarkWrite -benchmem

# Run with count for stability
go test -bench=. -benchmem -count=5

# Compare with benchstat
go test -bench=. -benchmem -count=10 > old.txt
# (make changes)
go test -bench=. -benchmem -count=10 > new.txt
benchstat old.txt new.txt

Output Interpretation

BenchmarkWrite/RingBuffer/64B-8    10000000    120 ns/op    0 B/op    0 allocs/op
BenchmarkWrite/LinkedList/64B-8    5000000     250 ns/op    64 B/op   1 allocs/op

Interpretation: RingBuffer ~2x faster, no allocations.

Rules (Non-negotiable)

1. Always use b.ResetTimer() after setup code
2. Always use b.ReportAllocs() for memory analysis
3. Same data sizes for fair comparison
4. Reset state between iterations
5. Clear naming convention: Operation/Implementation/Size
6. Run multiple times for stable results

Best Practices

Approval Prompt

After each step, ask:

"Please review the above and confirm if I should proceed to the next step."