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    SubjectRe: [patch 14/22] pollfs: pollable futex
    On Sun, 6 May 2007, Ulrich Drepper wrote:

    > On 5/5/07, Davide Libenzi <> wrote:
    > > But we have our own *sane* version of WaitForMultipleObjects, and it's
    > > called poll(2).
    > No, we don't. Don't start all over again. The interface of poll it
    > to primitive. See the kevent code, each record is, IIRC, 16 bytes in
    > size to return more data. For poll you only have bits.

    Yes, event bits plus opaque token are enough for most of it. Then you use
    POSIX read/write to fetch/store the data. All the files (sockets, pipes, ...)
    works this way. Signals you fetch a siginfo-like structure, through POSIX
    read. Timers, you fetch a counter, through POSIX read. AIO, you use the
    native AIO API (that I'd prefer, or you can choose to have a POSIX read
    too). All these through isolated POSIX read semantics.
    Now let's see how it'd look with a monolitic kevent-like interface. You'll
    have a mosnter-union ala siginfo_t, with multiple nested structures, and
    every time you need to extend it, you'll go through pain. Come on, that's
    beyond ugly. With a file-like interface, each new addition comes to a
    seaparate isolated interface, with separate POSIX read/write ABI.
    Do you realise that to justify your all new bulk interface,
    you had to pull out of the hat a Windows WaitForMultipleObjects?
    Please drop the BS. I made you a full list of things that are readily and
    POSIX-friendly handled/signaled with file-like interfaces.
    Any sockets, pipes, all devices, signals, timers, AIO, and I'm probably
    forgetting something.
    You pulled "it's slow". False.
    You pulled "it's memory expensive". It's not.
    So far, I did not hear a single valid reason to go with a new, monolitic
    interface. WaitForMultipleObjects? Please ...

    - Davide

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