Go Performance

Go Performance Patterns

Resource Routing

• scripts/bench-compare.sh - Run when comparing benchmark results, saving baselines, or producing JSON benchmark metadata.
• references/BENCHMARKS.md - Read when writing benchmarks, using benchstat, or profiling with pprof.
• references/STRING-OPTIMIZATION.md - Read when optimizing string conversion, concatenation, or byte/string boundaries.

Performance-specific guidelines apply only to the hot path. Don't prematurely optimize—focus these patterns where they matter most.

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Prefer strconv over fmt

When converting primitives to/from strings, strconv is faster than fmt:

s := strconv.Itoa(rand.Int()) // ~2x faster than fmt.Sprint()

Approach	Speed	Allocations
fmt.Sprint	143 ns/op	2 allocs/op
strconv.Itoa	64.2 ns/op	1 allocs/op

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Avoid Repeated String-to-Byte Conversions

Convert a fixed string to []byte once outside the loop:

data := []byte("Hello world")
for b.Loop() { // Go 1.24+; use b.N loops only for older Go
    w.Write(data) // ~7x faster than []byte("...") each iteration
}

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