Add benchmark

app/merger_test.go

@@ -1,6 +1,8 @@
 package app_test
 
 import (
+	"fmt"
+	"math/rand"
 	"testing"
 
 	"github.com/weaveworks/scope/app"
@@ -65,3 +67,45 @@ func TestSmartMerger(t *testing.T) {
 		t.Errorf("Bad merge: %s", test.Diff(have, want))
 	}
 }
+
+func BenchmarkSmartMerger(b *testing.B) {
+	benchmarMerger(b, app.NewSmartMerger())
+}
+
+func BenchmarkDumbMerger(b *testing.B) {
+	benchmarMerger(b, app.MakeDumbMerger())
+}
+
+const NUM_HOSTS = 15
+
+func benchmarMerger(b *testing.B, merger app.Merger) {
+	makeReport := func() report.Report {
+		rpt := report.MakeReport()
+		for i := 0; i < 100; i++ {
+			rpt.Endpoint.AddNode(report.MakeNode(fmt.Sprintf("%x", rand.Int63())))
+		}
+		return rpt
+	}
+
+	reports := []report.Report{}
+	for i := 0; i < NUM_HOSTS*5; i++ {
+		reports = append(reports, makeReport())
+	}
+	merger.Merge(reports) // prime the cache
+
+	b.ReportAllocs()
+	b.ResetTimer()
+
+	for i := 0; i < b.N; i++ {
+		b.StartTimer()
+
+		// replace 1/3 of hosts work of reports & merge them all
+		for i := 0; i < NUM_HOSTS/3; i++ {
+			reports[rand.Intn(len(reports))] = makeReport()
+		}
+
+		merger.Merge(reports)
+
+		b.StopTimer()
+	}
+}