Remove slower mergers

app/benchmark_internal_test.go

@@ -75,7 +75,7 @@ func BenchmarkReportMerge(b *testing.B) {
 func getReport(b *testing.B) report.Report {
 	r := fixture.Report
 	if *benchReportPath != "" {
-		r = NewSmartMerger().Merge(upgradeReports(readReportFiles(b, *benchReportPath)))
+		r = NewFastMerger().Merge(upgradeReports(readReportFiles(b, *benchReportPath)))
 	}
 	return r
 }

app/merger.go

@@ -13,54 +13,6 @@ type Merger interface {
 	Merge([]report.Report) report.Report
 }
 
-type dumbMerger struct{}
-
-// MakeDumbMerger makes a Merger which merges together reports in the simplest possible way.
-func MakeDumbMerger() Merger {
-	return dumbMerger{}
-}
-
-func (dumbMerger) Merge(reports []report.Report) report.Report {
-	rpt := report.MakeReport()
-	id := murmur3.New64()
-	for _, r := range reports {
-		rpt = rpt.Merge(r)
-		id.Write([]byte(r.ID))
-	}
-	rpt.ID = fmt.Sprintf("%x", id.Sum64())
-	return rpt
-}
-
-type smartMerger struct{}
-
-// NewSmartMerger makes a Merger which merges reports in
-// parallel. Speed up comes from the fact that a) most merges are
-// between small reports, and b) we take advantage of available cores.
-func NewSmartMerger() Merger {
-	return smartMerger{}
-}
-
-func (smartMerger) Merge(reports []report.Report) report.Report {
-	l := len(reports)
-	switch l {
-	case 0:
-		return report.MakeReport()
-	case 1:
-		return reports[0]
-	}
-	c := make(chan report.Report, l)
-	for _, r := range reports {
-		c <- r
-	}
-	for ; l > 1; l-- {
-		left, right := <-c, <-c
-		go func() {
-			c <- left.Merge(right)
-		}()
-	}
-	return <-c
-}
-
 type fastMerger struct{}
 
 // NewFastMerger makes a Merger which merges together reports, mutating the one we are building up

app/merger_test.go

@@ -27,7 +27,7 @@ func TestMerger(t *testing.T) {
 	want.Endpoint.AddNode(report.MakeNode("bar"))
 	want.Endpoint.AddNode(report.MakeNode("baz"))
 
-	for _, merger := range []app.Merger{app.MakeDumbMerger(), app.NewSmartMerger()} {
+	for _, merger := range []app.Merger{app.NewFastMerger()} {
 		// Test the empty list case
 		if have := merger.Merge([]report.Report{}); !reflect.DeepEqual(have, report.MakeReport()) {
 			t.Errorf("Bad merge: %s", test.Diff(have, want))
@@ -44,14 +44,6 @@ func TestMerger(t *testing.T) {
 	}
 }
 
-func BenchmarkSmartMerger(b *testing.B) {
-	benchmarkMerger(b, app.NewSmartMerger())
-}
-
-func BenchmarkDumbMerger(b *testing.B) {
-	benchmarkMerger(b, app.MakeDumbMerger())
-}
-
 func BenchmarkFastMerger(b *testing.B) {
 	benchmarkMerger(b, app.NewFastMerger())
 }