Optimization Techniques Skill

Performance optimization strategies for Go. ONLY use after profiling!

When to Use

Use ONLY after profiling identifies actual bottlenecks. NEVER optimize prematurely (KISS principle).

Pre-allocate Slices

// Good - pre-allocate when size known
items := make([]Item, 0, expectedSize)

// Bad - repeated allocations
var items []Item

Use strings.Builder

// Good
var b strings.Builder
for _, s := range strings {
    b.WriteString(s)
}
result := b.String()

// Bad - repeated allocations
result := ""
for _, s := range strings {
    result += s
}

sync.Pool for Reusable Objects

var bufferPool = sync.Pool{
    New: func() interface{} {
        return new(bytes.Buffer)
    },
}

buf := bufferPool.Get().(*bytes.Buffer)
defer bufferPool.Put(buf)
buf.Reset()
// use buf

Minimize Allocations

// Good - reuse buffer
buf := make([]byte, 1024)
for {
    n, _ := r.Read(buf)
    process(buf[:n])
}

// Bad - allocate each time
for {
    buf := make([]byte, 1024)
    n, _ := r.Read(buf)
    process(buf[:n])
}

Golden Rules

1. Profile first - Don't guess
2. Measure impact - Benchmark before/after
3. KISS principle - Simple first, optimize later
4. Maintain readability - Don't sacrifice clarity
5. Focus on hot paths - 80/20 rule