The following changes will help: 
my $var = "Subroutine Memory Leak";
$mw->Label( -textvariable => \$var )->pack;

sub autorefresh {
    # $var = $var + 20;
    $var += 20;
    return;
}

[download]

Don't create a label each time in sub autorefresh. You create a new label each time the sub is executed, but the previous one is still there. You are placing a label over a label over a label over a label...

--shmem

update: tested. Memory stays dead on at 7456/5064 VIRT/RES on my system. 

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}

In reply to Re^3: Subroutine Memory Leak by shmem
in thread Subroutine Memory Leak by gopika77

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