use strict;
use warnings;

#number of items to pack
my $iter = 1000000;
my $string;
my $startAlloc = 0;
my $preAllocSize = $startAlloc;

Time ();
$$string = '';

#now lets create the data block...
for my $count (1 .. $iter) {
    if ($preAllocSize && length ($$string) >= $preAllocSize) {
        $preAllocSize = length ($$string) * 2;
        my $newStr = 1 x $preAllocSize;
        $newStr = $$string;
        $string = \$newStr;
    }

    $$string .= 'x' x 20;
}
Time ();
print "Finished with start alloc: $startAlloc\n";
print "Final string length: ", length ($$string);

sub Time {
    my ($user, $system, $cuser, $csystem) = times;
    print "$user,$system\n";
}