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How Snow Leopard Cut ObjC Launch Time In Half

Posted by Soulskill on from the paring-down dept.

MBCook writes "Greg Parker has an excellent technical article on his blog about the changes to the dynamic linker (dyld) for Objective-C that Snow Leopard uses to cut launch time in half and cut about 1/2 MB of memory per application. 'In theory, a shared library could be different every time your program is run. In practice, you get the same version of the shared libraries almost every time you run, and so does every other process on the system. The system takes advantage of this by building the dyld shared cache. The shared cache contains a copy of many system libraries, with most of dyld's linking and loading work done in advance. Every process can then share that shared cache, saving memory and launch time.' He also has a post on the new thread-local garbage collection that Snow Leopard uses for Objective-C."

9 of 158 comments (clear)

  1. I've heard that before.... by LO0G · · Score: -1, Troll

    In other words, Apple just re-invented Superfetch

    Photocopiers anyone?

    1. Re:I've heard that before.... by sa666_666 · · Score: 0, Troll

      Also sounds like the prelink application in Linux.

    2. Re:I've heard that before.... by pizzach · · Score: 0, Troll
      I don't think so. From the article you linked:

      The intent is to improve performance in situations where running an anti-virus scan or back-up utility would result in otherwise recently-used information being paged out to disk, or disposed from in-memory caches, resulting in lengthy delays when a user comes back to their computer after a period of non-use.

      Everybody obviously knows that no viruses exist for the mac so your assertions are asymptotically false.

      --
      Once you start despising the jerks, you become one.
    3. Re:I've heard that before.... by pizzach · · Score: 0, Troll

      Actually, it is interesting I was marked troll for quoting some text that the original poster linked. O.o A view into the minds of the moderators.

      --
      Once you start despising the jerks, you become one.
  2. enough fucking by Anonymous Coward · · Score: 0, Troll

    snow leopard stories!

    1. Re:enough fucking by NoYob · · Score: 0, Troll
      What?!?

      Don't you understand that Snow Leopard is God's gift to operating systems?

      Objective-C happens to be the greatest programming language EVAR!

      Folks accuse Apple of re-inventing Superfetch. That is non-sense. Everything that Apple does is new and unique! It only seams as if Apple copies stuff because others come out with their own versions so fast that it sometimes seams as though they invented it first. But we all know that it was Apple who invented it first because their the ones who drive innovation in the PC world!

      Anyway, this story came out just in time! I'm on my way to Sunday Apple services at the local Apple store. The pastor was blessed by Jobs himself once at a MacWorld show! To be touched by a hand that was once touched by His Appleness is just spiritually uplifting!

      Praise Jobs - Glory Hallowed Be - Aaaaaaaaaamayyyen - Yaaaaeeeeeees!

      --
      It's NOT me! It's the meds! I'm on 1000mg of Fukitol.
  3. This is news... how? by Foredecker · · Score: -1, Troll

    So, Snow Leopard is now doing something Windows has always done... how is this news?

    --
    Jibe!
  4. Commen Sense Sharded Library by hackus · · Score: 0, Troll

    I do not wish to be a poo poo, but since dynamic libraries and shared libraries have been around for just about forever, when even a second year CS major would immediately notice this could be done, is such big news now?

    The first thing I would have done is built a cache for the library system. LINUX has one, why not the Mac?

    So certainly I congratulate the Mac community. But wow, DUH, a cache for the linkage editor. :-)

    -Hack

    --
    Got Geometrodynamics? Awe, too hard to figure out? Too bad.
  5. I have a question: Do you like The Beatles? by Anonymous Coward · · Score: -1, Troll

    Listen to your "theme song", by them. It's entitled: "I'm a LOSER"

    APK

    P.S.=> Fits you, perfectly... you've never done anything worth anything, & it shows. You truly are, the "ANONYMOUS COWARD", & because of that? You'll never amount to anything, & that is that... apk