Beefy Boxes and Bandwidth Generously Provided by pair Networks
Your skill will accomplish
what the force of many cannot

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??

Hi Nick.

I wonder if you could use an algorithm that could actually benefit both from parallel processing and from caching.

If you take your data set and interleaf it /8 or /12 (for your 12 cores), and then do the caching within each interleaf, you will have to regenerate the cache for each worker, but each worker maintains its own cache so that there's no per-iteration write back.

           iteration 1    iteration 2    iteration 3    iteration 4
worker 1       1               9              17              25
worker 2       2              10              18              26
worker 3       3              11              19              27
worker 4       4              12              20              28
worker 5       5              13              21              29
worker 6       6              14              22              30
worker 7       7              15              23              31
worker 8       8              16              24              32

So worker 1 gets 1, 9, 17, 25, ... to work on. Worker 2 gets 2, 10, 18, 26. Worker 3 gets 3, 11, 19, 27. And so on.

Within each worker implement caching. If I were using Parallel::ForkManager I would have them each return a structure identifying the worker starting offset, and the sequences. That way you don't have to compose them back into a master structure at the end for output, you can sequence them round-robin based on the starting offset of each.

I've sat down a few times today with the intent to give it a try, but keep getting interrupted before I get very far into it. So it's probably not going to happen.

Interleafing ought to allow each worker to build a cache pretty quickly.


In reply to Re: Optimizing with Caching vs. Parallelizing (MCE::Map) by davido
in thread Optimizing with Caching vs. Parallelizing (MCE::Map) by 1nickt

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, 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, 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.
  • Log In?

    What's my password?
    Create A New User
    and the web crawler heard nothing...

    How do I use this? | Other CB clients
    Other Users?
    Others pondering the Monastery: (3)
    As of 2020-10-22 07:39 GMT
    Find Nodes?
      Voting Booth?
      My favourite web site is:

      Results (225 votes). Check out past polls.