internal/trace: flags for what to include in GC utilization

Change-Id: I4ba963b003cb25b39d7575d423f17930d84f3f69
Reviewed-on: https://go-review.googlesource.com/c/60796
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>

src/cmd/trace/mmu.go

@@ -38,7 +38,7 @@ func getMMUCurve() ([]trace.MutatorUtil, *trace.MMUCurve, error) {
 		if err != nil {
 			mmuCache.err = err
 		} else {
-			mmuCache.util = tr.MutatorUtilization()
+			mmuCache.util = tr.MutatorUtilization(trace.UtilSTW | trace.UtilBackground | trace.UtilAssist)
 			mmuCache.mmuCurve = trace.NewMMUCurve(mmuCache.util)
 		}
 	})

src/internal/traceparser/gc.go

@@ -22,11 +22,27 @@ type MutatorUtil struct {
 	Util float64
 }
 
+// UtilFlags controls the behavior of MutatorUtilization.
+type UtilFlags int
+
+const (
+	// UtilSTW means utilization should account for STW events.
+	UtilSTW UtilFlags = 1 << iota
+	// UtilBackground means utilization should account for
+	// background mark workers.
+	UtilBackground
+	// UtilAssist means utilization should account for mark
+	// assists.
+	UtilAssist
+	// UtilSweep means utilization should account for sweeping.
+	UtilSweep
+)
+
 // MutatorUtilization returns the mutator utilization function for the
 // given trace. This function will always end with 0 utilization. The
 // bounds of the function are implicit in the first and last event;
 // outside of these bounds the function is undefined.
-func (p *Parsed) MutatorUtilization() []MutatorUtil {
+func (p *Parsed) MutatorUtilization(flags UtilFlags) []MutatorUtil {
 	events := p.Events
 	if len(events) == 0 {
 		return nil
@@ -42,17 +58,33 @@ func (p *Parsed) MutatorUtilization() []MutatorUtil {
 		case EvGomaxprocs:
 			gomaxprocs = int(ev.Args[0])
 		case EvGCSTWStart:
-			stw++
+			if flags&UtilSTW != 0 {
+				stw++
+			}
 		case EvGCSTWDone:
-			stw--
+			if flags&UtilSTW != 0 {
+				stw--
+			}
 		case EvGCMarkAssistStart:
-			gcPs++
-			assists[ev.G] = true
+			if flags&UtilAssist != 0 {
+				gcPs++
+				assists[ev.G] = true
+			}
 		case EvGCMarkAssistDone:
-			gcPs--
-			delete(assists, ev.G)
+			if flags&UtilAssist != 0 {
+				gcPs--
+				delete(assists, ev.G)
+			}
+		case EvGCSweepStart:
+			if flags&UtilSweep != 0 {
+				gcPs++
+			}
+		case EvGCSweepDone:
+			if flags&UtilSweep != 0 {
+				gcPs--
+			}
 		case EvGoStartLabel:
-			if strings.HasPrefix(ev.SArgs[0], "GC ") && ev.SArgs[0] != "GC (idle)" {
+			if flags&UtilBackground != 0 && strings.HasPrefix(ev.SArgs[0], "GC ") && ev.SArgs[0] != "GC (idle)" {
 				// Background mark worker.
 				bgMark[ev.G] = true
 				gcPs++

src/internal/traceparser/gc_test.go

@@ -84,7 +84,7 @@ func TestMMUTrace(t *testing.T) {
 	if err := p.Parse(0, 1<<62, nil); err != nil {
 		t.Fatalf("failed to parse trace: %s", err)
 	}
-	mu := p.MutatorUtilization()
+	mu := p.MutatorUtilization(UtilSTW | UtilBackground | UtilAssist)
 	mmuCurve := NewMMUCurve(mu)
 
 	// Test the optimized implementation against the "obviously
@@ -106,7 +106,7 @@ func BenchmarkMMU(b *testing.B) {
 	if err := p.Parse(0, 1<<62, nil); err != nil {
 		b.Fatalf("failed to parse trace: %s", err)
 	}
-	mu := p.MutatorUtilization()
+	mu := p.MutatorUtilization(UtilSTW | UtilBackground | UtilAssist | UtilSweep)
 	b.ResetTimer()
 
 	for i := 0; i < b.N; i++ {