seenNode := make(map[*Node]bool)
	seenEdge := make(map[nodePair]bool)
	for _, sample := range prof.Sample {
		var w, dw int64
		w = o.SampleValue(sample.Value)
		if o.SampleMeanDivisor != nil {
			dw = o.SampleMeanDivisor(sample.Value)
		}
		if dw == 0 && w == 0 {
			continue
		}
		for k := range seenNode {
			delete(seenNode, k)
		}
		for k := range seenEdge {
			delete(seenEdge, k)
		}

	seenNode := make(map[*Node]bool)
	seenEdge := make(map[nodePair]bool)
	for _, sample := range prof.Sample {
		var w, dw int64
		w = o.SampleValue(sample.Value)
		if o.SampleMeanDivisor != nil {
			dw = o.SampleMeanDivisor(sample.Value)
		}
		if dw == 0 && w == 0 {
			continue
		}
		for k := range seenNode {
			delete(seenNode, k)
		}
		for k := range seenEdge {
			delete(seenEdge, k)
		}

	formatTag := func(v int64, key string) string {
		return measurement.ScaledLabel(v, key, o.OutputUnit)
	}

	gopt := &graph.Options{
		SampleValue:       o.SampleValue,
		SampleMeanDivisor: o.SampleMeanDivisor,
		FormatTag:         formatTag,
		CallTree:          o.CallTree && (o.OutputFormat == Dot || o.OutputFormat == Callgrind),
		DropNegative:      o.DropNegative,
		KeptNodes:         nodes,
	}

		NodeCount:    cfg.NodeCount,
		NodeFraction: cfg.NodeFraction,
		EdgeFraction: cfg.EdgeFraction,

		ActiveFilters: filters,
		NumLabelUnits: numLabelUnits,

		SampleValue:       value,
		SampleMeanDivisor: meanDiv,
		SampleType:        stype,
		SampleUnit:        sample.Unit,

		OutputUnit: cfg.Unit,

		SourcePath: cfg.SourcePath,
		TrimPath:   cfg.TrimPath,

		IntelSyntax: cfg.IntelSyntax,

	}

	// Extract sample counts and compute set of interesting functions.
	for _, sample := range rpt.prof.Sample {
		value := rpt.options.SampleValue(sample.Value)
		if rpt.options.SampleMeanDivisor != nil {
			div := rpt.options.SampleMeanDivisor(sample.Value)
			if div != 0 {
				value /= div
			}
		}

		// Find call-sites matching sym.
		for i := len(sample.Location) - 1; i >= 0; i-- {
			loc := sample.Location[i]