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An Overview of Parallelism

Posted by kdawson on from the cores-galore dept.

Mortimer.CA writes with a recently released report from Berkeley entitled "The Landscape of Parallel Computing Research: A View from Berkeley: "Generally they conclude that the 'evolutionary approach to parallel hardware and software may work from 2- or 8-processor systems, but is likely to face diminishing returns as 16 and 32 processor systems are realized, just as returns fell with greater instruction-level parallelism.' This assumes things stay 'evolutionary' and that programming stays more or less how it has done in previous years (though languages like Erlang can probably help to change this)." Read on for Mortimer.CA's summary from the paper of some "conventional wisdoms" and their replacements.
Old and new conventional wisdoms:
  • Old CW: Power is free, but transistors are expensive.
  • New CW is the "Power wall": Power is expensive, but transistors are "free." That is, we can put more transistors on a chip than we have the power to turn on.

  • Old CW: Monolithic uniprocessors in silicon are reliable internally, with errors occurring only at the pins.
  • New CW: As chips drop below 65-nm feature sizes, they will have high soft and hard error rates.

  • Old CW: Multiply is slow, but load and store is fast.
  • New CW is the "Memory wall" [Wulf and McKee 1995]: Load and store is slow, but multiply is fast.

  • Old CW: Don't bother parallelizing your application, as you can just wait a little while and run it on a much faster sequential computer.
  • New CW: It will be a very long wait for a faster sequential computer (see above).

5 of 197 comments (clear)

  1. would that be by macadamia_harold · · Score: 5, Funny

    Mortimer.CA writes with a recently released report from Berkley entitled "The Landscape of Parallel Computing Research: A View from Berkeley

    Would that be a Parallelograph?

    --
    Push Button, Receive Bacon
    1. Re:would that be by Alwin+Henseler · · Score: 2, Funny

      No, more likely a Berks Eye View.

  2. From TFA by obender · · Score: 5, Funny

    The target should be 1000s of cores per chip
    640 cores should be enough for anyone.
  3. Erlang: The Movie by djberg96 · · Score: 2, Funny

    In case any has missed it: http://video.google.com/videoplay?docid=-583031888 2717959520

    I can't wait for the sequel!

    --
    In the immortal words of Socrates, "I drank what?"
  4. Re:Hmmm... by CosmeticLobotamy · · Score: 4, Funny

    Then we are doing something wrong. The human brain provides compelling evidence that massive parallelization works. So: what are we missing?

    Brain scalability is just not that great. Trust me, putting more than four brains in one head is just asking for locking problems out the yin-yang.