runtime/pprof, misc/pprof: correct profile of total allocations.

The previous heap profile format did not include buckets with
zero used bytes. Also add several missing MemStats fields in
debug mode.

R=golang-dev, rsc
CC=golang-dev, remy
https://golang.org/cl/6249068

misc/pprof

@@ -3753,15 +3753,19 @@ sub ReadHeapProfile {
         } else {
           # Remote-heap version 1
           my $ratio;
-          $ratio = (($s1*1.0)/$n1)/($sample_adjustment);
-          if ($ratio < 1) {
-            $n1 /= $ratio;
-            $s1 /= $ratio;
+          if ($n1 > 0) {
+            $ratio = (($s1*1.0)/$n1)/($sample_adjustment);
+            if ($ratio < 1) {
+                $n1 /= $ratio;
+                $s1 /= $ratio;
+            }
           }
-          $ratio = (($s2*1.0)/$n2)/($sample_adjustment);
-          if ($ratio < 1) {
-            $n2 /= $ratio;
-            $s2 /= $ratio;
+          if ($n2 > 0) {
+            $ratio = (($s2*1.0)/$n2)/($sample_adjustment);
+            if ($ratio < 1) {
+                $n2 /= $ratio;
+                $s2 /= $ratio;
+            }
           }
         }
       }

src/pkg/runtime/pprof/pprof.go

@@ -352,26 +352,26 @@ func WriteHeapProfile(w io.Writer) error {
 
 // countHeap returns the number of records in the heap profile.
 func countHeap() int {
-	n, _ := runtime.MemProfile(nil, false)
+	n, _ := runtime.MemProfile(nil, true)
 	return n
 }
 
 // writeHeapProfile writes the current runtime heap profile to w.
 func writeHeap(w io.Writer, debug int) error {
-	// Find out how many records there are (MemProfile(nil, false)),
+	// Find out how many records there are (MemProfile(nil, true)),
 	// allocate that many records, and get the data.
 	// There's a race—more records might be added between
 	// the two calls—so allocate a few extra records for safety
 	// and also try again if we're very unlucky.
 	// The loop should only execute one iteration in the common case.
 	var p []runtime.MemProfileRecord
-	n, ok := runtime.MemProfile(nil, false)
+	n, ok := runtime.MemProfile(nil, true)
 	for {
 		// Allocate room for a slightly bigger profile,
 		// in case a few more entries have been added
 		// since the call to MemProfile.
 		p = make([]runtime.MemProfileRecord, n+50)
-		n, ok = runtime.MemProfile(p, false)
+		n, ok = runtime.MemProfile(p, true)
 		if ok {
 			p = p[0:n]
 			break
@@ -431,11 +431,14 @@ func writeHeap(w io.Writer, debug int) error {
 		fmt.Fprintf(w, "# Sys = %d\n", s.Sys)
 		fmt.Fprintf(w, "# Lookups = %d\n", s.Lookups)
 		fmt.Fprintf(w, "# Mallocs = %d\n", s.Mallocs)
+		fmt.Fprintf(w, "# Frees = %d\n", s.Frees)
 
 		fmt.Fprintf(w, "# HeapAlloc = %d\n", s.HeapAlloc)
 		fmt.Fprintf(w, "# HeapSys = %d\n", s.HeapSys)
 		fmt.Fprintf(w, "# HeapIdle = %d\n", s.HeapIdle)
 		fmt.Fprintf(w, "# HeapInuse = %d\n", s.HeapInuse)
+		fmt.Fprintf(w, "# HeapReleased = %d\n", s.HeapReleased)
+		fmt.Fprintf(w, "# HeapObjects = %d\n", s.HeapObjects)
 
 		fmt.Fprintf(w, "# Stack = %d / %d\n", s.StackInuse, s.StackSys)
 		fmt.Fprintf(w, "# MSpan = %d / %d\n", s.MSpanInuse, s.MSpanSys)