cmd/vendor/.../pprof: sync at rev 1ddc9e2

This includes changes in pprof to support
 - the new -diff_base flag
 - fix for a bug in handling of legacy Go heap profiles

Update #25096

Change-Id: I826ac9244f31cc2c4415388c44a0cbe77303e460
Reviewed-on: https://go-review.googlesource.com/115295
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

8 files changed, 415 insertions, 64 deletions

diff --git a/src/cmd/vendor/github.com/google/pprof/internal/driver/cli.go b/src/cmd/vendor/github.com/google/pprof/internal/driver/cli.go
index c3c22e7c96..a5153e1511 100644
--- a/src/cmd/vendor/github.com/google/pprof/internal/driver/cli.go
+++ b/src/cmd/vendor/github.com/google/pprof/internal/driver/cli.go
@@ -15,6 +15,7 @@
 package driver
 
 import (
+	"errors"
 	"fmt"
 	"os"
 	"strings"
@@ -28,6 +29,7 @@ type source struct {
 	ExecName  string
 	BuildID   string
 	Base      []string
+	DiffBase  bool
 	Normalize bool
 
 	Seconds      int
@@ -43,7 +45,8 @@ type source struct {
 func parseFlags(o *plugin.Options) (*source, []string, error) {
 	flag := o.Flagset
 	// Comparisons.
-	flagBase := flag.StringList("base", "", "Source for base profile for comparison")
+	flagBase := flag.StringList("base", "", "Source for base profile for profile subtraction")
+	flagDiffBase := flag.StringList("diff_base", "", "Source for diff base profile for comparison")
 	// Source options.
 	flagSymbolize := flag.String("symbolize", "", "Options for profile symbolization")
 	flagBuildID := flag.String("buildid", "", "Override build id for first mapping")
@@ -85,7 +88,7 @@ func parseFlags(o *plugin.Options) (*source, []string, error) {
 			usageMsgVars)
 	})
 	if len(args) == 0 {
-		return nil, nil, fmt.Errorf("no profile source specified")
+		return nil, nil, errors.New("no profile source specified")
 	}
 
 	var execName string
@@ -112,7 +115,7 @@ func parseFlags(o *plugin.Options) (*source, []string, error) {
 		return nil, nil, err
 	}
 	if cmd != nil && *flagHTTP != "" {
-		return nil, nil, fmt.Errorf("-http is not compatible with an output format on the command line")
+		return nil, nil, errors.New("-http is not compatible with an output format on the command line")
 	}
 
 	si := pprofVariables["sample_index"].value
@@ -140,15 +143,13 @@ func parseFlags(o *plugin.Options) (*source, []string, error) {
 		Comment:      *flagAddComment,
 	}
 
-	for _, s := range *flagBase {
-		if *s != "" {
-			source.Base = append(source.Base, *s)
-		}
+	if err := source.addBaseProfiles(*flagBase, *flagDiffBase); err != nil {
+		return nil, nil, err
 	}
 
 	normalize := pprofVariables["normalize"].boolValue()
 	if normalize && len(source.Base) == 0 {
-		return nil, nil, fmt.Errorf("Must have base profile to normalize by")
+		return nil, nil, errors.New("must have base profile to normalize by")
 	}
 	source.Normalize = normalize
 
@@ -158,6 +159,34 @@ func parseFlags(o *plugin.Options) (*source, []string, error) {
 	return source, cmd, nil
 }
 
+// addBaseProfiles adds the list of base profiles or diff base profiles to
+// the source. This function will return an error if both base and diff base
+// profiles are specified.
+func (source *source) addBaseProfiles(flagBase, flagDiffBase []*string) error {
+	base, diffBase := dropEmpty(flagBase), dropEmpty(flagDiffBase)
+	if len(base) > 0 && len(diffBase) > 0 {
+		return errors.New("-base and -diff_base flags cannot both be specified")
+	}
+
+	source.Base = base
+	if len(diffBase) > 0 {
+		source.Base, source.DiffBase = diffBase, true
+	}
+	return nil
+}
+
+// dropEmpty list takes a slice of string pointers, and outputs a slice of
+// non-empty strings associated with the flag.
+func dropEmpty(list []*string) []string {
+	var l []string
+	for _, s := range list {
+		if *s != "" {
+			l = append(l, *s)
+		}
+	}
+	return l
+}
+
 // installFlags creates command line flags for pprof variables.
 func installFlags(flag plugin.FlagSet) flagsInstalled {
 	f := flagsInstalled{
@@ -240,7 +269,7 @@ func outputFormat(bcmd map[string]*bool, acmd map[string]*string) (cmd []string,
 	for n, b := range bcmd {
 		if *b {
 			if cmd != nil {
-				return nil, fmt.Errorf("must set at most one output format")
+				return nil, errors.New("must set at most one output format")
 			}
 			cmd = []string{n}
 		}
@@ -248,7 +277,7 @@ func outputFormat(bcmd map[string]*bool, acmd map[string]*string) (cmd []string,
 	for n, s := range acmd {
 		if *s != "" {
 			if cmd != nil {
-				return nil, fmt.Errorf("must set at most one output format")
+				return nil, errors.New("must set at most one output format")
 			}
 			cmd = []string{n, *s}
 		}
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/driver/driver.go b/src/cmd/vendor/github.com/google/pprof/internal/driver/driver.go
index acc0b4ad8a..2dabc3017b 100644
--- a/src/cmd/vendor/github.com/google/pprof/internal/driver/driver.go
+++ b/src/cmd/vendor/github.com/google/pprof/internal/driver/driver.go
@@ -65,7 +65,13 @@ func generateRawReport(p *profile.Profile, cmd []string, vars variables, o *plug
 	// Identify units of numeric tags in profile.
 	numLabelUnits := identifyNumLabelUnits(p, o.UI)
 
-	vars = applyCommandOverrides(cmd, vars)
+	// Get report output format
+	c := pprofCommands[cmd[0]]
+	if c == nil {
+		panic("unexpected nil command")
+	}
+
+	vars = applyCommandOverrides(cmd[0], c.format, vars)
 
 	// Delay focus after configuring report to get percentages on all samples.
 	relative := vars["relative_percentages"].boolValue()
@@ -78,10 +84,6 @@ func generateRawReport(p *profile.Profile, cmd []string, vars variables, o *plug
 	if err != nil {
 		return nil, nil, err
 	}
-	c := pprofCommands[cmd[0]]
-	if c == nil {
-		panic("unexpected nil command")
-	}
 	ropt.OutputFormat = c.format
 	if len(cmd) == 2 {
 		s, err := regexp.Compile(cmd[1])
@@ -149,13 +151,10 @@ func generateReport(p *profile.Profile, cmd []string, vars variables, o *plugin.
 	return out.Close()
 }
 
-func applyCommandOverrides(cmd []string, v variables) variables {
+func applyCommandOverrides(cmd string, outputFormat int, v variables) variables {
 	trim, tagfilter, filter := v["trim"].boolValue(), true, true
 
-	switch cmd[0] {
-	case "proto", "raw":
-		trim, tagfilter, filter = false, false, false
-		v.set("addresses", "t")
+	switch cmd {
 	case "callgrind", "kcachegrind":
 		trim = false
 		v.set("addresses", "t")
@@ -163,7 +162,7 @@ func applyCommandOverrides(cmd []string, v variables) variables {
 		trim = false
 		v.set("addressnoinlines", "t")
 	case "peek":
-		trim, filter = false, false
+		trim, tagfilter, filter = false, false, false
 	case "list":
 		v.set("nodecount", "0")
 		v.set("lines", "t")
@@ -176,6 +175,12 @@ func applyCommandOverrides(cmd []string, v variables) variables {
 			v.set("nodecount", "80")
 		}
 	}
+
+	if outputFormat == report.Proto || outputFormat == report.Raw {
+		trim, tagfilter, filter = false, false, false
+		v.set("addresses", "t")
+	}
+
 	if !trim {
 		v.set("nodecount", "0")
 		v.set("nodefraction", "0")
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/driver/driver_test.go b/src/cmd/vendor/github.com/google/pprof/internal/driver/driver_test.go
index 309e9950b6..ff6afe9cff 100644
--- a/src/cmd/vendor/github.com/google/pprof/internal/driver/driver_test.go
+++ b/src/cmd/vendor/github.com/google/pprof/internal/driver/driver_test.go
@@ -288,7 +288,7 @@ type testFlags struct {
 	floats      map[string]float64
 	strings     map[string]string
 	args        []string
-	stringLists map[string][]*string
+	stringLists map[string][]string
 }
 
 func (testFlags) ExtraUsage() string { return "" }
@@ -355,7 +355,12 @@ func (f testFlags) StringVar(p *string, s, d, c string) {
 
 func (f testFlags) StringList(s, d, c string) *[]*string {
 	if t, ok := f.stringLists[s]; ok {
-		return &t
+		// convert slice of strings to slice of string pointers before returning.
+		tp := make([]*string, len(t))
+		for i, v := range t {
+			tp[i] = &v
+		}
+		return &tp
 	}
 	return &[]*string{}
 }
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/driver/fetch.go b/src/cmd/vendor/github.com/google/pprof/internal/driver/fetch.go
index 7c576de614..7a7a1a20f2 100644
--- a/src/cmd/vendor/github.com/google/pprof/internal/driver/fetch.go
+++ b/src/cmd/vendor/github.com/google/pprof/internal/driver/fetch.go
@@ -63,6 +63,9 @@ func fetchProfiles(s *source, o *plugin.Options) (*profile.Profile, error) {
 	}
 
 	if pbase != nil {
+		if s.DiffBase {
+			pbase.SetLabel("pprof::base", []string{"true"})
+		}
 		if s.Normalize {
 			err := p.Normalize(pbase)
 			if err != nil {
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/driver/fetch_test.go b/src/cmd/vendor/github.com/google/pprof/internal/driver/fetch_test.go
index afb135b7cd..e67b2e9f87 100644
--- a/src/cmd/vendor/github.com/google/pprof/internal/driver/fetch_test.go
+++ b/src/cmd/vendor/github.com/google/pprof/internal/driver/fetch_test.go
@@ -210,13 +210,20 @@ func TestFetchWithBase(t *testing.T) {
 	baseVars := pprofVariables
 	defer func() { pprofVariables = baseVars }()
 
+	type WantSample struct {
+		values []int64
+		labels map[string][]string
+	}
+
 	const path = "testdata/"
 	type testcase struct {
-		desc            string
-		sources         []string
-		bases           []string
-		normalize       bool
-		expectedSamples [][]int64
+		desc         string
+		sources      []string
+		bases        []string
+		diffBases    []string
+		normalize    bool
+		wantSamples  []WantSample
+		wantErrorMsg string
 	}
 
 	testcases := []testcase{
@@ -224,58 +231,216 @@ func TestFetchWithBase(t *testing.T) {
 			"not normalized base is same as source",
 			[]string{path + "cppbench.contention"},
 			[]string{path + "cppbench.contention"},
+			nil,
+			false,
+			nil,
+			"",
+		},
+		{
+			"not normalized base is same as source",
+			[]string{path + "cppbench.contention"},
+			[]string{path + "cppbench.contention"},
+			nil,
 			false,
-			[][]int64{},
+			nil,
+			"",
 		},
 		{
 			"not normalized single source, multiple base (all profiles same)",
 			[]string{path + "cppbench.contention"},
 			[]string{path + "cppbench.contention", path + "cppbench.contention"},
+			nil,
 			false,
-			[][]int64{{-2700, -608881724}, {-100, -23992}, {-200, -179943}, {-100, -17778444}, {-100, -75976}, {-300, -63568134}},
+			[]WantSample{
+				{
+					values: []int64{-2700, -608881724},
+					labels: map[string][]string{},
+				},
+				{
+					values: []int64{-100, -23992},
+					labels: map[string][]string{},
+				},
+				{
+					values: []int64{-200, -179943},
+					labels: map[string][]string{},
+				},
+				{
+					values: []int64{-100, -17778444},
+					labels: map[string][]string{},
+				},
+				{
+					values: []int64{-100, -75976},
+					labels: map[string][]string{},
+				},
+				{
+					values: []int64{-300, -63568134},
+					labels: map[string][]string{},
+				},
+			},
+			"",
 		},
 		{
 			"not normalized, different base and source",
 			[]string{path + "cppbench.contention"},
 			[]string{path + "cppbench.small.contention"},
+			nil,
 			false,
-			[][]int64{{1700, 608878600}, {100, 23992}, {200, 179943}, {100, 17778444}, {100, 75976}, {300, 63568134}},
+			[]WantSample{
+				{
+					values: []int64{1700, 608878600},
+					labels: map[string][]string{},
+				},
+				{
+					values: []int64{100, 23992},
+					labels: map[string][]string{},
+				},
+				{
+					values: []int64{200, 179943},
+					labels: map[string][]string{},
+				},
+				{
+					values: []int64{100, 17778444},
+					labels: map[string][]string{},
+				},
+				{
+					values: []int64{100, 75976},
+					labels: map[string][]string{},
+				},
+				{
+					values: []int64{300, 63568134},
+					labels: map[string][]string{},
+				},
+			},
+			"",
 		},
 		{
 			"normalized base is same as source",
 			[]string{path + "cppbench.contention"},
 			[]string{path + "cppbench.contention"},
+			nil,
 			true,
-			[][]int64{},
+			nil,
+			"",
 		},
 		{
 			"normalized single source, multiple base (all profiles same)",
 			[]string{path + "cppbench.contention"},
 			[]string{path + "cppbench.contention", path + "cppbench.contention"},
+			nil,
 			true,
-			[][]int64{},
+			nil,
+			"",
 		},
 		{
 			"normalized different base and source",
 			[]string{path + "cppbench.contention"},
 			[]string{path + "cppbench.small.contention"},
+			nil,
 			true,
-			[][]int64{{-229, -370}, {28, 0}, {57, 0}, {28, 80}, {28, 0}, {85, 287}},
+			[]WantSample{
+				{
+					values: []int64{-229, -370},
+					labels: map[string][]string{},
+				},
+				{
+					values: []int64{28, 0},
+					labels: map[string][]string{},
+				},
+				{
+					values: []int64{57, 0},
+					labels: map[string][]string{},
+				},
+				{
+					values: []int64{28, 80},
+					labels: map[string][]string{},
+				},
+				{
+					values: []int64{28, 0},
+					labels: map[string][]string{},
+				},
+				{
+					values: []int64{85, 287},
+					labels: map[string][]string{},
+				},
+			},
+			"",
+		},
+		{
+			"not normalized diff base is same as source",
+			[]string{path + "cppbench.contention"},
+			nil,
+			[]string{path + "cppbench.contention"},
+			false,
+			[]WantSample{
+				{
+					values: []int64{2700, 608881724},
+					labels: map[string][]string{},
+				},
+				{
+					values: []int64{100, 23992},
+					labels: map[string][]string{},
+				},
+				{
+					values: []int64{200, 179943},
+					labels: map[string][]string{},
+				},
+				{
+					values: []int64{100, 17778444},
+					labels: map[string][]string{},
+				},
+				{
+					values: []int64{100, 75976},
+					labels: map[string][]string{},
+				},
+				{
+					values: []int64{300, 63568134},
+					labels: map[string][]string{},
+				},
+				{
+					values: []int64{-2700, -608881724},
+					labels: map[string][]string{"pprof::base": {"true"}},
+				},
+				{
+					values: []int64{-100, -23992},
+					labels: map[string][]string{"pprof::base": {"true"}},
+				},
+				{
+					values: []int64{-200, -179943},
+					labels: map[string][]string{"pprof::base": {"true"}},
+				},
+				{
+					values: []int64{-100, -17778444},
+					labels: map[string][]string{"pprof::base": {"true"}},
+				},
+				{
+					values: []int64{-100, -75976},
+					labels: map[string][]string{"pprof::base": {"true"}},
+				},
+				{
+					values: []int64{-300, -63568134},
+					labels: map[string][]string{"pprof::base": {"true"}},
+				},
+			},
+			"",
+		},
+		{
+			"diff_base and base both specified",
+			[]string{path + "cppbench.contention"},
+			[]string{path + "cppbench.contention"},
+			[]string{path + "cppbench.contention"},
+			false,
+			nil,
+			"-base and -diff_base flags cannot both be specified",
 		},
 	}
 
 	for _, tc := range testcases {
 		t.Run(tc.desc, func(t *testing.T) {
 			pprofVariables = baseVars.makeCopy()
-
-			base := make([]*string, len(tc.bases))
-			for i, s := range tc.bases {
-				base[i] = &s
-			}
-
 			f := testFlags{
-				stringLists: map[string][]*string{
-					"base": base,
+				stringLists: map[string][]string{
+					"base":      tc.bases,
+					"diff_base": tc.diffBases,
 				},
 				bools: map[string]bool{
 					"normalize": tc.normalize,
@@ -289,30 +454,37 @@ func TestFetchWithBase(t *testing.T) {
 			})
 			src, _, err := parseFlags(o)
 
+			if tc.wantErrorMsg != "" {
+				if err == nil {
+					t.Fatalf("got nil, want error %q", tc.wantErrorMsg)
+				}
+
+				if gotErrMsg := err.Error(); gotErrMsg != tc.wantErrorMsg {
+					t.Fatalf("got error %q, want error %q", gotErrMsg, tc.wantErrorMsg)
+				}
+				return
+			}
+
 			if err != nil {
-				t.Fatalf("%s: %v", tc.desc, err)
+				t.Fatalf("got error %q, want no error", err)
 			}
 
 			p, err := fetchProfiles(src, o)
-			pprofVariables = baseVars
+
 			if err != nil {
-				t.Fatal(err)
+				t.Fatalf("got error %q, want no error", err)
 			}
 
-			if want, got := len(tc.expectedSamples), len(p.Sample); want != got {
-				t.Fatalf("want %d samples got %d", want, got)
+			if got, want := len(p.Sample), len(tc.wantSamples); got != want {
+				t.Fatalf("got %d samples want %d", got, want)
 			}
 
-			if len(p.Sample) > 0 {
-				for i, sample := range p.Sample {
-					if want, got := len(tc.expectedSamples[i]), len(sample.Value); want != got {
-						t.Errorf("want %d values for sample %d, got %d", want, i, got)
-					}
-					for j, value := range sample.Value {
-						if want, got := tc.expectedSamples[i][j], value; want != got {
-							t.Errorf("want value of %d for value %d of sample %d, got %d", want, j, i, got)
-						}
-					}
+			for i, sample := range p.Sample {
+				if !reflect.DeepEqual(tc.wantSamples[i].values, sample.Value) {
+					t.Errorf("for sample %d got values %v, want %v", i, sample.Value, tc.wantSamples[i])
+				}
+				if !reflect.DeepEqual(tc.wantSamples[i].labels, sample.Label) {
+					t.Errorf("for sample %d got labels %v, want %v", i, sample.Label, tc.wantSamples[i].labels)
 				}
 			}
 		})
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/driver/interactive_test.go b/src/cmd/vendor/github.com/google/pprof/internal/driver/interactive_test.go
index db26862c7d..8d775e16bd 100644
--- a/src/cmd/vendor/github.com/google/pprof/internal/driver/interactive_test.go
+++ b/src/cmd/vendor/github.com/google/pprof/internal/driver/interactive_test.go
@@ -294,7 +294,13 @@ func TestInteractiveCommands(t *testing.T) {
 			t.Errorf("failed on %q: %v", tc.input, err)
 			continue
 		}
-		vars = applyCommandOverrides(cmd, vars)
+
+		// Get report output format
+		c := pprofCommands[cmd[0]]
+		if c == nil {
+			t.Errorf("unexpected nil command")
+		}
+		vars = applyCommandOverrides(cmd[0], c.format, vars)
 
 		for n, want := range tc.want {
 			if got := vars[n].stringValue(); got != want {
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/report/report.go b/src/cmd/vendor/github.com/google/pprof/internal/report/report.go
index 15cadfb548..76db9cbf99 100644
--- a/src/cmd/vendor/github.com/google/pprof/internal/report/report.go
+++ b/src/cmd/vendor/github.com/google/pprof/internal/report/report.go
@@ -264,6 +264,10 @@ func (rpt *Report) newGraph(nodes graph.NodeSet) *graph.Graph {
 		s.NumUnit = numUnits
 	}
 
+	// Remove label marking samples from the base profiles, so it does not appear
+	// as a nodelet in the graph view.
+	prof.RemoveLabel("pprof::base")
+
 	formatTag := func(v int64, key string) string {
 		return measurement.ScaledLabel(v, key, o.OutputUnit)
 	}
@@ -1212,10 +1216,11 @@ func NewDefault(prof *profile.Profile, options Options) *Report {
 	return New(prof, o)
 }
 
-// computeTotal computes the sum of all sample values. This will be
-// used to compute percentages.
+// computeTotal computes the sum of the absolute value of all sample values.
+// If any samples have the label "pprof::base" with value "true", then the total
+// will only include samples with that label.
 func computeTotal(prof *profile.Profile, value, meanDiv func(v []int64) int64) int64 {
-	var div, ret int64
+	var div, total, diffDiv, diffTotal int64
 	for _, sample := range prof.Sample {
 		var d, v int64
 		v = value(sample.Value)
@@ -1225,13 +1230,21 @@ func computeTotal(prof *profile.Profile, value, meanDiv func(v []int64) int64) i
 		if v < 0 {
 			v = -v
 		}
-		ret += v
+		total += v
 		div += d
+		if sample.HasLabel("pprof::base", "true") {
+			diffTotal += v
+			diffDiv += d
+		}
+	}
+	if diffTotal > 0 {
+		total = diffTotal
+		div = diffDiv
 	}
 	if div != 0 {
-		return ret / div
+		return total / div
 	}
-	return ret
+	return total
 }
 
 // Report contains the data and associated routines to extract a
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/report/report_test.go b/src/cmd/vendor/github.com/google/pprof/internal/report/report_test.go
index 49c6e4934f..9eb435bbb8 100644
--- a/src/cmd/vendor/github.com/google/pprof/internal/report/report_test.go
+++ b/src/cmd/vendor/github.com/google/pprof/internal/report/report_test.go
@@ -287,3 +287,121 @@ func TestLegendActiveFilters(t *testing.T) {
 		}
 	}
 }
+
+func TestComputeTotal(t *testing.T) {
+	p1 := testProfile.Copy()
+	p1.Sample = []*profile.Sample{
+		{
+			Location: []*profile.Location{testL[0]},
+			Value:    []int64{1, 1},
+		},
+		{
+			Location: []*profile.Location{testL[2], testL[1], testL[0]},
+			Value:    []int64{1, 10},
+		},
+		{
+			Location: []*profile.Location{testL[4], testL[2], testL[0]},
+			Value:    []int64{1, 100},
+		},
+	}
+
+	p2 := testProfile.Copy()
+	p2.Sample = []*profile.Sample{
+		{
+			Location: []*profile.Location{testL[0]},
+			Value:    []int64{1, 1},
+		},
+		{
+			Location: []*profile.Location{testL[2], testL[1], testL[0]},
+			Value:    []int64{1, -10},
+		},
+		{
+			Location: []*profile.Location{testL[4], testL[2], testL[0]},
+			Value:    []int64{1, 100},
+		},
+	}
+
+	p3 := testProfile.Copy()
+	p3.Sample = []*profile.Sample{
+		{
+			Location: []*profile.Location{testL[0]},
+			Value:    []int64{10000, 1},
+		},
+		{
+			Location: []*profile.Location{testL[2], testL[1], testL[0]},
+			Value:    []int64{-10, 3},
+			Label:    map[string][]string{"pprof::base": {"true"}},
+		},
+		{
+			Location: []*profile.Location{testL[2], testL[1], testL[0]},
+			Value:    []int64{1000, -10},
+		},
+		{
+			Location: []*profile.Location{testL[2], testL[1], testL[0]},
+			Value:    []int64{-9000, 3},
+			Label:    map[string][]string{"pprof::base": {"true"}},
+		},
+		{
+			Location: []*profile.Location{testL[2], testL[1], testL[0]},
+			Value:    []int64{-1, 3},
+			Label:    map[string][]string{"pprof::base": {"true"}},
+		},
+		{
+			Location: []*profile.Location{testL[4], testL[2], testL[0]},
+			Value:    []int64{100, 100},
+		},
+		{
+			Location: []*profile.Location{testL[2], testL[1], testL[0]},
+			Value:    []int64{100, 3},
+			Label:    map[string][]string{"pprof::base": {"true"}},
+		},
+	}
+
+	testcases := []struct {
+		desc           string
+		prof           *profile.Profile
+		value, meanDiv func(v []int64) int64
+		wantTotal      int64
+	}{
+		{
+			desc: "no diff base, all positive values, index 1",
+			prof: p1,
+			value: func(v []int64) int64 {
+				return v[0]
+			},
+			wantTotal: 3,
+		},
+		{
+			desc: "no diff base, all positive values, index 2",
+			prof: p1,
+			value: func(v []int64) int64 {
+				return v[1]
+			},
+			wantTotal: 111,
+		},
+		{
+			desc: "no diff base, some negative values",
+			prof: p2,
+			value: func(v []int64) int64 {
+				return v[1]
+			},
+			wantTotal: 111,
+		},
+		{
+			desc: "diff base, some negative values",
+			prof: p3,
+			value: func(v []int64) int64 {
+				return v[0]
+			},
+			wantTotal: 9111,
+		},
+	}
+
+	for _, tc := range testcases {
+		t.Run(tc.desc, func(t *testing.T) {
+			if gotTotal := computeTotal(tc.prof, tc.value, tc.meanDiv); gotTotal != tc.wantTotal {
+				t.Errorf("got total %d, want %v", gotTotal, tc.wantTotal)
+			}
+		})
+	}
+}