Modified dotgraph tag labels so they aren't scaled to graph's unit (#168)

internal/driver/driver_test.go

 		{"dot,functions,flat", "cpu"},
 		{"dot,functions,flat,call_tree", "cpu"},
 		{"dot,lines,flat,focus=[12]00", "heap"},
+		{"dot,unit=minimum", "heap_sizetags"},
 		{"dot,addresses,flat,ignore=[X3]002,focus=[X1]000", "contention"},
 		{"dot,files,cum", "contention"},
 		{"comments", "cpu"},
 			{Type: "alloc_objects", Unit: "count"},
 			{Type: "alloc_space", Unit: "bytes"},
 		}
+	case "heap_sizetags":
+		p = heapProfile()
+		tags := []int64{2, 4, 8, 16, 32, 64, 128, 256}
+		for _, s := range p.Sample {
+			s.NumLabel["bytes"] = append(s.NumLabel["bytes"], tags...)
+		}
+
 	case "contention":
 		p = contentionProfile()
 	case "symbolz":

internal/driver/testdata/pprof.heap_sizetags.dot

+digraph "unnamed" {
+node [style=filled fillcolor="#f8f8f8"]
+subgraph cluster_L { "Build ID: buildid" [shape=box fontsize=16 label="Build ID: buildid\lcomment\lType: inuse_space\lShowing nodes accounting for 93.75MB, 95.05% of 98.63MB total\lDropped 1 node (cum <= 4.93MB)\l"] }
+N1 [label="line3002\n31.25MB (31.68%)\nof 94.73MB (96.04%)" fontsize=20 shape=box tooltip="line3002 (94.73MB)" color="#b20200" fillcolor="#edd5d5"]
+NN1_0 [label = "16B..64B" fontsize=8 shape=box3d tooltip="93.75MB"]
+N1 -> NN1_0 [label=" 93.75MB" weight=100 tooltip="93.75MB" labeltooltip="93.75MB"]
+NN1_1 [label = "2B..8B" fontsize=8 shape=box3d tooltip="93.75MB"]
+N1 -> NN1_1 [label=" 93.75MB" weight=100 tooltip="93.75MB" labeltooltip="93.75MB"]
+NN1_2 [label = "256B..1.56MB" fontsize=8 shape=box3d tooltip="62.50MB"]
+N1 -> NN1_2 [label=" 62.50MB" weight=100 tooltip="62.50MB" labeltooltip="62.50MB"]
+NN1_3 [label = "128B" fontsize=8 shape=box3d tooltip="31.25MB"]
+N1 -> NN1_3 [label=" 31.25MB" weight=100 tooltip="31.25MB" labeltooltip="31.25MB"]
+N2 [label="line3000\n0 of 98.63MB (100%)" fontsize=8 shape=box tooltip="line3000 (98.63MB)" color="#b20000" fillcolor="#edd5d5"]
+N3 [label="line2001\n62.50MB (63.37%)\nof 63.48MB (64.36%)" fontsize=24 shape=box tooltip="line2001 (63.48MB)" color="#b21600" fillcolor="#edd8d5"]
+NN3_0 [label = "16B..64B" fontsize=8 shape=box3d tooltip="190.43MB"]
+N3 -> NN3_0 [label=" 190.43MB" weight=100 tooltip="190.43MB" labeltooltip="190.43MB" style="dotted"]
+NN3_1 [label = "2B..8B" fontsize=8 shape=box3d tooltip="190.43MB"]
+N3 -> NN3_1 [label=" 190.43MB" weight=100 tooltip="190.43MB" labeltooltip="190.43MB" style="dotted"]
+NN3_2 [label = "256B..1.56MB" fontsize=8 shape=box3d tooltip="125.98MB"]
+N3 -> NN3_2 [label=" 125.98MB" weight=100 tooltip="125.98MB" labeltooltip="125.98MB" style="dotted"]
+NN3_3 [label = "128B" fontsize=8 shape=box3d tooltip="63.48MB"]
+N3 -> NN3_3 [label=" 63.48MB" weight=100 tooltip="63.48MB" labeltooltip="63.48MB" style="dotted"]
+N4 [label="line2000\n0 of 63.48MB (64.36%)" fontsize=8 shape=box tooltip="line2000 (63.48MB)" color="#b21600" fillcolor="#edd8d5"]
+N5 [label="line3001\n0 of 36.13MB (36.63%)" fontsize=8 shape=box tooltip="line3001 (36.13MB)" color="#b22e00" fillcolor="#eddbd5"]
+N4 -> N3 [label=" 63.48MB\n (inline)" weight=65 penwidth=4 color="#b21600" tooltip="line2000 -> line2001 (63.48MB)" labeltooltip="line2000 -> line2001 (63.48MB)"]
+N1 -> N4 [label=" 63.48MB" weight=65 penwidth=4 color="#b21600" tooltip="line3002 -> line2000 (63.48MB)" labeltooltip="line3002 -> line2000 (63.48MB)" minlen=2]
+N2 -> N1 [label=" 62.50MB\n (inline)" weight=64 penwidth=4 color="#b21600" tooltip="line3000 -> line3002 (62.50MB)" labeltooltip="line3000 -> line3002 (62.50MB)"]
+N2 -> N5 [label=" 36.13MB\n (inline)" weight=37 penwidth=2 color="#b22e00" tooltip="line3000 -> line3001 (36.13MB)" labeltooltip="line3000 -> line3001 (36.13MB)"]
+N5 -> N1 [label=" 32.23MB\n (inline)" weight=33 penwidth=2 color="#b23200" tooltip="line3001 -> line3002 (32.23MB)" labeltooltip="line3001 -> line3002 (32.23MB)"]
+}

internal/graph/dotgraph.go

 	LegendURL string   // The URL to link to from the legend.
 	Labels    []string // The labels for the DOT's legend
 
-	FormatValue func(int64) string         // A formatting function for values
-	FormatTag   func(int64, string) string // A formatting function for numeric tags
-	Total       int64                      // The total weight of the graph, used to compute percentages
+	FormatValue func(int64) string // A formatting function for values
+	Total       int64              // The total weight of the graph, used to compute percentages
 }
 
 const maxNodelets = 4 // Number of nodelets for labels (both numeric and non)
 }
 
 func (b *builder) tagGroupLabel(g []*Tag) (label string, flat, cum int64) {
-	formatTag := b.config.FormatTag
-	if formatTag == nil {
-		formatTag = measurement.Label
-	}
-
 	if len(g) == 1 {
 		t := g[0]
-		return formatTag(t.Value, t.Unit), t.FlatValue(), t.CumValue()
+		return measurement.Label(t.Value, t.Unit), t.FlatValue(), t.CumValue()
 	}
 	min := g[0]
 	max := g[0]
 	if dc != 0 {
 		c = c / dc
 	}
-	return formatTag(min.Value, min.Unit) + ".." + formatTag(max.Value, max.Unit), f, c
+
+	// Tags are not scaled with the selected output unit because tags are often
+	// much smaller than other values which appear, so the range of tag sizes
+	// sometimes would appear to be "0..0" when scaled to the selected output unit.
+	return measurement.Label(min.Value, min.Unit) + ".." + measurement.Label(max.Value, max.Unit), f, c
 }
 
 func min64(a, b int64) int64 {

internal/report/report.go

 	rpt.selectOutputUnit(g)
 	labels := reportLabels(rpt, g, origCount, droppedNodes, droppedEdges, true)
 
-	o := rpt.options
-	formatTag := func(v int64, key string) string {
-		return measurement.ScaledLabel(v, key, o.OutputUnit)
-	}
-
 	c := &graph.DotConfig{
 		Title:       rpt.options.Title,
 		Labels:      labels,
 		FormatValue: rpt.formatValue,
-		FormatTag:   formatTag,
 		Total:       rpt.total,
 	}
 	return g, c