Performance and memory profiling Go concat vs fmt.Sprintf

result

go test -bench=.  -memprofile=mem0.out -benchmem -benchtime=5s
goos: darwin
goarch: amd64
pkg: github.com/InVisionApp/craft-api/util
BenchmarkHello/concat-8                 300000000               19.8 ns/op             0 B/op          0 allocs/op
BenchmarkHello/sprintf-8                50000000               119 ns/op              19 B/op          2 allocs/op
PASS

test_test.go

package test

import (
	"fmt"
	"testing"
)

func BenchmarkHello(b *testing.B) {
	str := "2"
	b.Run("concat", func(b *testing.B) {
		for i := 0; i < b.N; i++ {
			s := str + "xx"
			_ = s
		}
	})

	b.Run("sprintf", func(b *testing.B) {
		for i := 0; i < b.N; i++ {
			s := fmt.Sprintf("%sxx", str)
			_ = s
		}
	})
}