Hi,

the execution time of your script without fork is very good. You should make a simple test, how much time is spent for Perl startup. Forking is a relative expensive action. So you have to be sure that it's worth it. In your case it seems to be not. Have a look at Devel::NYTProf to profile your code.

UPDATE: With your forking code you allow up to 50 childs of the main process. This seems to be much too much. The whole task you want to optimize is IO bound (scanning the directory tree, reading in files, writing the files). You don't gain much when many processes are fighting for the same resource. When you just want to optimize in terms of computing power I would allow as much subprocesses as you have CPU cores in your computer.

It would be interesting to test the following approach: Scan the whole directory tree and push all found mp3 files on a array (job queue), then split the queue into N parts (N = number of cores) and start N subprocesses working on their subqueue. In this case you do only fork once per subqueue and not for every file (which is expensive).

Best regards
McA

In reply to Re: No Performance gain with Parallel::ForkManager by McA
in thread No Performance gain with Parallel::ForkManager by walto

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.