#! perl -slw
use strict;
use threads;
use threads::shared;

my %bighash :shared = map{
    $_ => 1;
} 'aaa' .. 'zzz';

sub thread {
     while( 1 ) {
        lock %bighash;
        1 while each %bighash;
     }
}

my @threads = map{
    threads->create( \&thread );
} 1 .. 8;

$_->join for @threads;