to sum up the article, in linux, application uses shared libraries and the shared libraries are being shared among other applications. but it is still only one copy of shared library. ps aux gives you the memory usage on the process itself and the shared library too.

so, try run ps aux to grab your perl proc id.then run pmap -d Proc_ID. the mapped: result at the bottom line is the total memory usage including shared libraries. writeable/private is the one without counting the shared libraries.

my sshd pmap output:

mapped: 3652K    writeable/private: 804K    shared: 0K
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