Reading between the lines of your last couple of OPs, you seem to be parsing multiple XML files with XML::Simple; and doing so in threads in the hope of preventing leaks?

From a couple of quick experiments, it seems that whichever underlying parser -- XML::SAX, XML::SAX::PurePerl, XML::Parser -- you use, they all leak substantial amounts of memory. XML::SAX more so that XML::Parser, but still in the range of 10 to 30MB per iteration for a 12MB xml file.

My suggestion to cure that -- essentially what Zentara suggested earlier, but with a twist -- is to run the parser in a separate process. I used this to parse the file and then export the structure back to the parent:

#! perl -slw
use strict;
use Storable qw[ freeze ];
use XML::Simple; $XML::Simple::PREFERRED_PARSER = 'XML::Parser'; 

binmode STDOUT;
print freeze XMLin( $ARGV[ 0 ] );
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And then in the main script just a simple backticks command and thaw:

for( 1 .. 1000 ) {
    my $xml = thaw `xmlSto.pl junk.xml`;
    print mem $_; <STDIN>;
}
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It took about 1 extra second or so for the parent process to get access to the data structure, but it cures the leak completely.