When I tried some threaded code I found that the &share() function was next to useless for hashes and arrays. The documentation (threads::shared) appears to pretty much agree:

BUGS AND LIMITATIONS

When share is used on arrays, hashes, array refs or hash refs, any data they contain will be lost.

I found that the trick was to declare shared arrays/hashes. Then you can put references to those shared items into other shared data structures.

So, where you have:

sub thread_worker {
        my $n = shift;     # thread N
        my @args = shift;
        my %temp = ();
        ....
        while(1) {
            ....
            $totals{$n}->{STEPS} = $s;              # record step
            $temp{$s}=$random;                      # add value to per
+-thread hash 
            $totals{$n}->{HASH}= &share( \%temp );  # copy results to 
+shared structure
            ....
        }
}
[download]

I would try:

sub thread_worker {
        my $n = shift;                      # thread N
        my @args = shift;
        my %temp : shared = ();             # Make shared

        $totals{$n}->{STEPS} = 0 ;          # Nothing yet
        $totals{$n}->{HASH}  = \%temp ;     # Set ref to shared result
+s
        ....
        while(1) {
            ....
            $totals{$n}->{STEPS} = $s;      # record step
            $temp{$s}=$random;              # add value to per-thread 
+hash 
# REMOVED:  $totals{$n}->{HASH}= &share( \%temp );
            ....
        }
}
[download]

and see if it works any better. (It did for me.)