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    SubjectRe: newidle balancing in NUMA domain?
    > Quite a few being one test case, and on a program with a horrible
    > parallelism design (rapid heavy weight forks to distribute small
    > units of work).

    > If x264 is declared dainbramaged, that's fine with me too.

    We did multiple benchmarks using a thread pool and it did not help.
    If you want to declare our app "braindamaged", feel free, but pooling
    threads to avoid re-creation gave no benefit whatsoever. If you think
    the parallelism methodology is wrong as a whole, you're basically
    saying that Linux shouldn't be used for video compression, because
    this is the exact same threading model used by almost every single
    video encoder ever made. There are actually a few that use
    slice-based threading, but those are actually even worse from your
    perspective, because slice-based threading spawns mulitple threads PER
    FRAME instead of one per frame.

    Because of the inter-frame dependencies in video coding it is
    impossible to efficiently get a granularity of more than one thread
    per frame. Pooling threads doesn't change the fact that you are
    conceptually creating a thread for each frame--it just eliminates the
    pthread_create call. In theory you could do one thread per group of
    frames, but that is completely unrealistic for real-time encoding
    (e.g. streaming), requires a catastrophically large amount of memory,
    makes it impossible to track the bit buffer, and all other sorts of
    bad stuff.

    Jason Garrett-Glaser

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      Last update: 2009-11-24 18:27    [W:0.023 / U:9.272 seconds]
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