http1 vs h2c

main.go

package main

import (
	"context"
	"crypto/tls"
	"fmt"
	"io"
	"io/ioutil"
	"net"
	"net/http"
	"sync/atomic"
	"time"

	"golang.org/x/net/http2"
	"golang.org/x/net/http2/h2c"
)

func main() {
	srv := &http.Server{
		Addr: ":8080",
		Handler: h2c.NewHandler(
			http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
				w.Write([]byte("OK"))
			}),
			&http2.Server{},
		),
	}
	go srv.ListenAndServe()

	time.Sleep(100 * time.Millisecond)

	var dialCnt uint64

	bench := func(name string, client *http.Client) {
		dialCnt = 0

		var (
			okCnt  uint64
			errCnt uint64
		)

		request := func() {
			resp, err := client.Get("http://127.0.0.1:8080")
			if err != nil {
				atomic.AddUint64(&errCnt, 1)
				return
			}
			io.Copy(ioutil.Discard, resp.Body)
			resp.Body.Close()
			atomic.AddUint64(&okCnt, 1)
		}

		ctx, _ := context.WithTimeout(context.Background(), 10*time.Second)

		for i := 0; i < 8; i++ {
			go func() {
				for j := 0; j < 200; j++ {
					go func() {
						for {
							select {
							case <-ctx.Done():
								return
							default:
								request()
							}
						}
					}()
				}
			}()
		}

		<-ctx.Done()
		fmt.Printf("%s\ndial: %d times\nok: %d req/s\nerr: %d total\n", name, dialCnt, okCnt/10, errCnt)
	}

	bench("http1", &http.Client{
		Transport: &http.Transport{
			DialContext: func(ctx context.Context, network, addr string) (conn net.Conn, err error) {
				atomic.AddUint64(&dialCnt, 1)
				return net.Dial(network, addr)
			},
			DisableCompression:  true,
			MaxIdleConnsPerHost: 200,
		},
	})

	bench("h2c", &http.Client{
		Transport: &http2.Transport{
			DialTLS: func(network, addr string, cfg *tls.Config) (conn net.Conn, err error) {
				atomic.AddUint64(&dialCnt, 1)
				return net.Dial(network, addr)
			},
			DisableCompression: true,
			AllowHTTP:          true,
		},
	})
}