} 👾[go-webapp]$ 🔥 Delete compiled test, and collect benchmark data 👾[go-webapp]$ rm -v hello-go.test removed 'hello-go.test' 👾[go-webapp]$ go test -cpuprofile cpu-refactored.prof -bench . goos: linux goarch: amd64 pkg: hello-go BenchmarkHelloServer/run_bench-2 24349323 44.3 ns/op PASS ok hello-go 1.317s 👾[go-webapp]$ 🔥 show cpu profile for io.WriteString 👾[go-webapp]$ go tool pprof -list io.WriteString cpu-refactored.prof | head Total: 1.20s ROUTINE ======================== io.WriteString in /usr/lib/golang/src/io/io.go 150ms 760ms (flat, cum) 63.33% of Total . . 285: . . 286:// WriteString writes the contents of the string s to w, which accepts a slice of bytes. . . 287:// If w implements StringWriter, its WriteString method is invoked directly. . . 288:// Otherwise, w.Write is called exactly once. . . 289:func WriteString(w Writer, s string) (n int, err error) { 50ms 420ms 290: if sw, ok := w.(StringWriter); ok { 100ms 340ms 291: return sw.WriteString(s) 👾[go-webapp]$