Benchmark comparison

metrics/engine/ingester_test.go

@@ -4,6 +4,7 @@ import (
 	"strconv"
 	"testing"
 
+	"github.com/clarkduvall/hyperloglog"
 	"github.com/sirupsen/logrus"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -221,3 +222,43 @@ func newTestPreInitState(tb testing.TB) *lib.TestPreInitState {
 		BuiltinMetrics: metrics.RegisterBuiltinMetrics(reg),
 	}
 }
+
+func cardinalityMap() {
+	m := make(map[uint64]struct{})
+	for i := 1; i <= 100000; i++ {
+		m[uint64(i)] = struct{}{}
+	}
+}
+
+func cardinalityHLL() {
+	hll, _ := hyperloglog.NewPlus(10)
+	for i := 1; i <= 100000; i++ {
+		hll.Add(hyperWrap(i))
+	}
+}
+
+type hyperWrap int
+
+func (hw hyperWrap) Sum64() uint64 {
+	return uint64(hw)
+}
+
+// goos: linux
+// goarch: amd64
+// pkg: go.k6.io/k6/metrics/engine
+// cpu: AMD Ryzen 7 4800H with Radeon Graphics
+// BenchmarkDiffMap-16    	      72	  14654822 ns/op	 3274790 B/op	    3928 allocs/op
+// BenchmarkDiffHLL-16    	      93	  11855822 ns/op	  800565 B/op	   99758 allocs/op
+// PASS
+// ok  	go.k6.io/k6/metrics/engine	2.204s
+func BenchmarkDiffMap(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		cardinalityMap()
+	}
+}
+
+func BenchmarkDiffHLL(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		cardinalityHLL()
+	}
+}