sub cmpthese_times {
    my $rows = shift;
    my @widths;

    for my $row (@$rows) {
        next if $row->[1] =~ s/Rate/Time/;
        
        my ($value) = $row->[1] =~ m!(\d+)/s!;
        
        next unless defined $value;
        $row->[1] = sprintf '%6.2es', 1.0 / $value;
    }
    
    for my $row (@$rows) {
        $widths[$_] = max ($widths[$_] || 0, 1 + length $row->[$_]) for 0 .. $#$row;
    }
    
    my $format = "%-$widths[0]s";
    $format .= "%$widths[$_]s" for 1 .. $#widths;
    $format .= "\n";
    
    printf $format, @$_ for @$rows;
}