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    SubjectRe: [patch 00/11] ANNOUNCE: "Syslets", generic asynchronous system call support

    * Evgeniy Polyakov <> wrote:

    > [...] it still has a problem - syscall blocks and the same thread thus
    > is not allowed to continue execution and fill the pipe - so what if
    > system issues thousands of requests and there are only tens of working
    > thread at most. [...]

    the same thread is allowed to continue execution even if the system call
    blocks: take a look at async_schedule(). The blocked system-call is 'put
    aside' (in a sleeping thread), the kernel switches the user-space
    context (registers) to a free kernel thread and switches to it - and
    returns to user-space as if nothing happened - allowing the user-space
    context to 'fill the pipe' as much as it can. Or did i misunderstand
    your point?

    basically there's SYSLET_ASYNC for 'always async' and SYSLET_SYNC for
    'always sync' - but the default syslet behavior is: 'try sync and switch
    transparently to async on demand'. The testcode i sent very much uses
    this. (and this mechanism is in essence Zach's fibril-switching thing,
    but done via kernel threads.)

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      Last update: 2007-02-13 23:23    [W:0.021 / U:8.516 seconds]
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