Problems I found with your code:

• Your design looks wrong: you'll be creating a table row for every key in %$all_names for every element in @arr_of_names.
• Reading through the entire @arr_of_names for every key in %$all_names is unecessary and inefficient.
• Assigning to $txt for every key in %$all_names for every element in @arr_of_names is unecessary and inefficient.
• Concatenating text to $table for every key in %$all_names for every element in @arr_of_names is unecessary and inefficient.
• You don't declare the hashref $all_names or show its data.

Here's how I might have tackled this type of problem:

$ perl -Mstrict -Mwarnings -le '
    my @all_names = qw{Mary Ken John Ann};
    my @good_names = qw{Mary John Ann};
    my %all_name_data = map { $_ => 1 } @all_names;
    my %is_good_name = map { $_ => 1 } @good_names;

    print "<table>";
    for (sort keys %all_name_data) {
        print "\t<tr><td>",
              $is_good_name{$_} ? "GOOD" : "BAD",
              " - $_</td></tr>";
    }
    print "</table>";
'
<table>
    <tr><td>GOOD - Ann</td></tr>
    <tr><td>GOOD - John</td></tr>
    <tr><td>BAD - Ken</td></tr>
    <tr><td>GOOD - Mary</td></tr>
</table>
[download]

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