net/http: add TLS benchmark

R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/110080045

src/pkg/net/http/serve_test.go

@@ -2559,24 +2559,43 @@ func BenchmarkClientServer(b *testing.B) {
 }
 
 func BenchmarkClientServerParallel4(b *testing.B) {
-	benchmarkClientServerParallel(b, 4)
+	benchmarkClientServerParallel(b, 4, false)
 }
 
 func BenchmarkClientServerParallel64(b *testing.B) {
-	benchmarkClientServerParallel(b, 64)
+	benchmarkClientServerParallel(b, 64, false)
 }
 
-func benchmarkClientServerParallel(b *testing.B, parallelism int) {
+func BenchmarkClientServerParallelTLS4(b *testing.B) {
+	benchmarkClientServerParallel(b, 4, true)
+}
+
+func BenchmarkClientServerParallelTLS64(b *testing.B) {
+	benchmarkClientServerParallel(b, 64, true)
+}
+
+func benchmarkClientServerParallel(b *testing.B, parallelism int, useTLS bool) {
 	b.ReportAllocs()
-	ts := httptest.NewServer(HandlerFunc(func(rw ResponseWriter, r *Request) {
+	ts := httptest.NewUnstartedServer(HandlerFunc(func(rw ResponseWriter, r *Request) {
 		fmt.Fprintf(rw, "Hello world.\n")
 	}))
+	if useTLS {
+		ts.StartTLS()
+	} else {
+		ts.Start()
+	}
 	defer ts.Close()
 	b.ResetTimer()
 	b.SetParallelism(parallelism)
 	b.RunParallel(func(pb *testing.PB) {
+		noVerifyTransport := &Transport{
+			TLSClientConfig: &tls.Config{
+				InsecureSkipVerify: true,
+			},
+		}
+		client := &Client{Transport: noVerifyTransport}
 		for pb.Next() {
-			res, err := Get(ts.URL)
+			res, err := client.Get(ts.URL)
 			if err != nil {
 				b.Logf("Get: %v", err)
 				continue