Add benchmarks for the code changes in ac16dc9

name                            old time/op    new time/op    delta
NewSampleFromTrail/no_failed-8    1.08µs ± 6%    1.02µs ± 6%   ~     (p=0.095 n=5+5)
NewSampleFromTrail/failed-8       2.20µs ± 5%    2.22µs ± 3%   ~     (p=0.841 n=5+5)
name                            old alloc/op   new alloc/op   delta
NewSampleFromTrail/no_failed-8      336B ± 0%      336B ± 0%   ~     (all equal)
NewSampleFromTrail/failed-8         752B ± 0%      752B ± 0%   ~     (all equal)
name                            old allocs/op  new allocs/op  delta
NewSampleFromTrail/no_failed-8      4.00 ± 0%      4.00 ± 0%   ~     (all equal)
NewSampleFromTrail/failed-8         5.00 ± 0%      5.00 ± 0%   ~     (all equal)

name                                         old time/op    new time/op    delta
MeasureAndEmitMetrics/no_responseCallback-8    6.71µs ± 3%    6.82µs ± 2%     ~     (p=0.421 n=5+5)
MeasureAndEmitMetrics/responseCallback-8       8.13µs ± 8%    7.16µs ± 3%  -11.96%  (p=0.008 n=5+5)
name                                         old alloc/op   new alloc/op   delta
MeasureAndEmitMetrics/no_responseCallback-8    1.03kB ± 0%    1.10kB ± 0%   +6.20%  (p=0.008 n=5+5)
MeasureAndEmitMetrics/responseCallback-8       1.80kB ± 0%    1.10kB ± 0%  -39.11%  (p=0.008 n=5+5)
name                                         old allocs/op  new allocs/op  delta
MeasureAndEmitMetrics/no_responseCallback-8      9.00 ± 0%      9.00 ± 0%     ~     (all equal)
MeasureAndEmitMetrics/responseCallback-8         10.0 ± 0%       9.0 ± 0%  -10.00%  (p=0.008 n=5+5)

lib/netext/httpext/transport_test.go

@@ -0,0 +1,86 @@
+/*
+ *
+ * k6 - a next-generation load testing tool
+ * Copyright (C) 2021 Load Impact
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+package httpext
+
+import (
+	"context"
+	"net/http"
+	"net/url"
+	"testing"
+
+	"github.com/loadimpact/k6/lib"
+	"github.com/loadimpact/k6/stats"
+	"github.com/sirupsen/logrus"
+)
+
+func BenchmarkMeasureAndEmitMetrics(b *testing.B) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	samples := make(chan stats.SampleContainer, 10)
+	defer close(samples)
+	go func() {
+		for range samples {
+		}
+	}()
+	logger := logrus.New()
+	logger.Level = logrus.DebugLevel
+
+	state := &lib.State{
+		Options: lib.Options{
+			RunTags:    &stats.SampleTags{},
+			SystemTags: &stats.DefaultSystemTagSet,
+		},
+		Samples: samples,
+		Logger:  logger,
+	}
+	t := transport{
+		state: state,
+		ctx:   ctx,
+	}
+
+	b.ResetTimer()
+	unfRequest := &unfinishedRequest{
+		tracer: &Tracer{},
+		response: &http.Response{
+			StatusCode: 200,
+		},
+		request: &http.Request{
+			URL: &url.URL{
+				Host:   "example.com",
+				Scheme: "https",
+			},
+		},
+	}
+
+	b.Run("no responseCallback", func(b *testing.B) {
+		for i := 0; i < b.N; i++ {
+			t.measureAndEmitMetrics(unfRequest)
+		}
+	})
+
+	t.responseCallback = func(n int) bool { return true }
+
+	b.Run("responseCallback", func(b *testing.B) {
+		for i := 0; i < b.N; i++ {
+			t.measureAndEmitMetrics(unfRequest)
+		}
+	})
+}

stats/cloud/bench_test.go

@@ -330,3 +330,33 @@ func BenchmarkHTTPPush(b *testing.B) {
 		})
 	}
 }
+
+func BenchmarkNewSampleFromTrail(b *testing.B) {
+	tags := generateTags(1, 200)
+	now := time.Now()
+	trail := &httpext.Trail{
+		Blocked:        200 * 100 * time.Millisecond,
+		Connecting:     200 * 200 * time.Millisecond,
+		TLSHandshaking: 200 * 300 * time.Millisecond,
+		Sending:        200 * 400 * time.Millisecond,
+		Waiting:        500 * time.Millisecond,
+		Receiving:      600 * time.Millisecond,
+		EndTime:        now,
+		ConnDuration:   500 * time.Millisecond,
+		Duration:       150 * 1500 * time.Millisecond,
+		Tags:           tags,
+	}
+
+	b.Run("no failed", func(b *testing.B) {
+		for s := 0; s < b.N; s++ {
+			_ = NewSampleFromTrail(trail)
+		}
+	})
+	trail.Failed = null.BoolFrom(true)
+
+	b.Run("failed", func(b *testing.B) {
+		for s := 0; s < b.N; s++ {
+			_ = NewSampleFromTrail(trail)
+		}
+	})
+}