Benchmark results for patch set 1 of https://go-review.googlesource.com/#/c/29243/1

benchcmp-results.txt

[ma@march benchcmp]? benchcmp http2-req-orig.txt http2-req-patch-set-1.txt
benchmark                                        old ns/op     new ns/op     delta
BenchmarkClientRequestHeaders/___0_Headers-4     253637        256495        +1.13%
BenchmarkClientRequestHeaders/__10_Headers-4     302833        307072        +1.40%
BenchmarkClientRequestHeaders/_100_Headers-4     771251        773099        +0.24%
BenchmarkClientRequestHeaders/1000_Headers-4     7970480       8012981       +0.53%

benchmark                                        old allocs     new allocs     delta
BenchmarkClientRequestHeaders/___0_Headers-4     53             57             +7.55%
BenchmarkClientRequestHeaders/__10_Headers-4     85             90             +5.88%
BenchmarkClientRequestHeaders/_100_Headers-4     368            376            +2.17%
BenchmarkClientRequestHeaders/1000_Headers-4     5138           5145           +0.14%

benchmark                                        old bytes     new bytes     delta
BenchmarkClientRequestHeaders/___0_Headers-4     4493          5113          +13.80%
BenchmarkClientRequestHeaders/__10_Headers-4     6126          7397          +20.75%
BenchmarkClientRequestHeaders/_100_Headers-4     29300         39969         +36.41%
BenchmarkClientRequestHeaders/1000_Headers-4     338151        431371        +27.57%

BenchmarkClientRequestHeaders.go

func benchSimpleRoundTrip(b *testing.B, nHeaders int) {
	defer disableGoroutineTracking()()
	b.ReportAllocs()
	st := newServerTester(b,
		func(w http.ResponseWriter, r *http.Request) {
		},
		optOnlyServer,
		optQuiet,
	)
	defer st.Close()

	tr := &Transport{TLSClientConfig: tlsConfigInsecure}
	defer tr.CloseIdleConnections()

	req, err := http.NewRequest("GET", st.ts.URL, nil)
	if err != nil {
		b.Fatal(err)
	}

	for i := 0; i < nHeaders; i++ {
		name := fmt.Sprint("A-", i)
		req.Header.Set(name, "*")
	}

	b.ResetTimer()

	for i := 0; i < b.N; i++ {
		res, err := tr.RoundTrip(req)
		if err != nil {
			if res != nil {
				res.Body.Close()
			}
			b.Fatalf("RoundTrip err = %v; want nil", err)
		}
		res.Body.Close()
		if res.StatusCode != http.StatusOK {
			b.Fatalf("Response code = %v; want %v", res.StatusCode, http.StatusOK)
		}
	}
}

func BenchmarkClientRequestHeaders(b *testing.B) {
	b.Run("   0 Headers", func(b *testing.B) { benchSimpleRoundTrip(b, 0) })
	b.Run("  10 Headers", func(b *testing.B) { benchSimpleRoundTrip(b, 10) })
	b.Run(" 100 Headers", func(b *testing.B) { benchSimpleRoundTrip(b, 100) })
	b.Run("1000 Headers", func(b *testing.B) { benchSimpleRoundTrip(b, 1000) })
}