This is from the ModPerl Cookbook, pulled from pages 317-322 (i'm quoting mixed with some paraphrasing).

The B::Size and B::TerseSize modules, both part of the B::Size distribution, include a number of routines to calculate memory usage of perl packages, subroutines and variables.

It goes on to describe how to set it up with Apache::Status on a mod_perl server to get useful information displayed by Apache::Status. If you would like more info on that, msg me and I will give it to you. But if you are not running mod_perl, then i would just look at the B::Size documentation. I cannot speak for it, as i have never used or known of anyone who has used it, but this Cookbook has never let me down before, so I weigh its suggestions pretty highly.

The book then goes on to talk about reducing memory consumption by not exporting symbols from modules, basically doing this: 


use POSIX ();

# instead of this ...

use POSIX;

[download]

POSIX imports over 560 symbols, each imported symbol being about a 120 byte memory penalty. According to this book that works out to 140KB of memery overhead that could be avoided with 2 colons and a little more typing. Not alot in a small one-off script, but that piles up fast when you have 50-100 mod_perl/Apache child processes screaming for attention from the CPU.

But as anyone who has been around in this biz for over 18 months (the cycle time for Moore's Law) will tell you. Don't worry about stuff like this too much unless you know for absolutely sure its a problem, because chances are in another 18 months,... well you know.

-stvn

In reply to Re: module memory usage by stvn
in thread module memory usage by smackdab

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