my @col_widths;

    my @top_row = ( 
        '', 
	$display_as_rate ? 'Rate' : 's/iter', 
	map { $_->[0] } @vals 
    );

    push @rows, \@top_row;
    @col_widths = map { length( $_ ) } @top_row;

    # Build the data rows
    # We leave the last column in even though it never has any data.  Perhaps
    # it should go away.  Also, perhaps a style for a single column of
    # percentages might be nice.
    for my $row_val ( @vals ) {
	my @row;

        # Column 0 = test name
	push @row, $row_val->[0];
	$col_widths[0] = length( $row_val->[0] )
	    if length( $row_val->[0] ) > $col_widths[0];

        # Column 1 = performance
	my $row_rate = $row_val->[7];

	# We assume that we'll never get a 0 rate.
	my $rate = $display_as_rate ? $row_rate : 1 / $row_rate;

	# Only give a few decimal places before switching to sci. notation,
	# since the results aren't usually that accurate anyway.
	my $format = 
	   $rate >= 100 ? 
	       "%0.0f" : 
	   $rate >= 10 ?
	       "%0.1f" :
	   $rate >= 1 ?
	       "%0.2f" :
	   $rate >= 0.1 ?
	       "%0.3f" :
	       "%0.2e";

	$format .= "/s"
	    if $display_as_rate;

	my $formatted_rate = sprintf( $format, $rate );
	push @row, $formatted_rate;
	$col_widths[1] = length( $formatted_rate )
	    if length( $formatted_rate ) > $col_widths[1];

        # Columns 2..N = performance ratios
	my $skip_rest = 0;
	for ( my $col_num = 0 ; $col_num < @vals ; ++$col_num ) {
	    my $col_val = $vals[$col_num];
	    my $out;
	    if ( $skip_rest ) {
		$out = '';
	    }
	    elsif ( $col_val->[0] eq $row_val->[0] ) {
		$out = "--";
		# $skip_rest = 1;
	    }
	    else {
		my $col_rate = $col_val->[7];
		$out = sprintf( "%.0f%%", 100*$row_rate/$col_rate - 100 );
	    }
	    push @row, $out;
	    $col_widths[$col_num+2] = length( $out )
		if length( $out ) > $col_widths[$col_num+2];

	    # A little wierdness to set the first column width properly
	    $col_widths[$col_num+2] = length( $col_val->[0] )
		if length( $col_val->[0] ) > $col_widths[$col_num+2];
	}
	push @rows, \@row;
    }

    return \@rows if $style eq "none";

    # Equalize column widths in the chart as much as possible without
    # exceeding 80 characters.  This does not use or affect cols 0 or 1.
    my @sorted_width_refs = 
       sort { $$a <=> $$b } map { \$_ } @col_widths[2..$#col_widths];
    my $max_width = ${$sorted_width_refs[-1]};

    my $total = @col_widths - 1 ;
    for ( @col_widths ) { $total += $_ }

    STRETCHER:
    while ( $total < 80 ) {
	my $min_width = ${$sorted_width_refs[0]};
	last
	   if $min_width == $max_width;
	for ( @sorted_width_refs ) {
	    last 
		if $$_ > $min_width;
	    ++$$_;
	    ++$total;
	    last STRETCHER
		if $total >= 80;