Does Perl have garbage collection mechanism and how it performs?

[RobCheung]

Hi monks, Does Perl have garbage collection mechanism and how it performs?

#-----------------------------------------------------------
use 5.008;
use strict;
use threads qw(yield);
use threads::shared ();
use Time::HiRes qw(sleep);

our @GlobalArray : shared = (1..1000);

my $sub1 = sub {
    while (1) {
        my $a;
        { lock @GlobalArray; $a = shift @GlobalArray; }
        print $a, "\n";
        yield;
        sleep 0.05;
    }
};

my $t1 = new threads $sub1;
my $t2 = new threads $sub1;
my $t3 = new threads $sub1;

$t1->detach;
$t2->detach;
$t3->detach;

while (1) {
    # readFile();
    # ...

    push @GlobalArray, (1..1000) unless scalar @GlobalArray;
    sleep 0.001;
}

1;
#-----------------------------------------------------------

This is a simple example, but it has a serious problem (on Windows 2000) that the used memory will increase by 200kb after every "push", and it will be out of memory soon. I wonder that how the GC mechanism performs? Is there any way to fix the problem by collect some leaked memory during the runing time? Thanks advance for any help!