while (my $t = shift(@ready)){
     $shash{$t}{'data'} = shift @to_be_processed;
     $shash{$t}{'go'} = 1; 
}

##</code><code>##

my @tready = @ready;
@ready();
while (my $t = shift(@tready)){
     $shash{$t}{'data'} = shift @to_be_processed;
     $shash{$t}{'go'} = 1; 
}