use strict;
    use warnings;
    use threads;
    use Time::HiRes 'time';

    my $nr_children = 1;
    my @threads;
    my $start = time;

    foreach my $i (1 .. $nr_children) {
        $threads[$i] = threads->create(\&Work, $i);
    }
    foreach my $i (1 .. $nr_children) {
        $threads[$i]->join();
    }

    my $stop = time - $start;
    printf "\nclock: %.1f sec\n", $stop;
    my @run = times;
    printf "user:  %.1f sec\n", $run[0];

exit;

#####

sub Work {
    my ($i) = @_;

    foreach ( 1 .. (20e5/$nr_children) ) {
        my $acct_nrs = "abc\txyz\tdef\tabc\tghi\tghi";
        my @temp = split(m/\t/, $acct_nrs, -1);
        @temp = ( sort keys %{{ map { $_ => 1 } @temp }} );
        my $ans = join(', ', @temp);
    }
    print " $i";
    return;
}