lkml.org 
[lkml]   [2006]   [Jul]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: A better interface, perhaps: a timed signal flag
    From
    Date
    On Fri, 2006-07-28 at 17:41 +0100, Alan Cox wrote:
    > Ar Gwe, 2006-07-28 am 10:52 -0400, ysgrifennodd Theodore Tso:
    > > Good point, and limiting this facility to one such timeout per
    > > task_struct seems like a reasonable restriction.
    >
    > Why is this any better than using a thread or signal handler ? From the
    > implementation side its certainly horrible - we will be trying to write
    > user pages from an IRQ event. Far better to let the existing thread code
    > deal with it.
    >

    If the user page is special, in that it is really a kernel page mapped
    to userspace. The implementation on making sure it doesn't disappear on
    the interrupt isn't that difficult.

    But for real-time applications, the signal handling has a huge latency.
    Where as what Theodore wants to do is very light weight. ie. have a
    high prio task doing smaller tasks until a specific time that tells it
    to stop. Having a signal, would create the latency on having that task
    stop.

    These little requests make sense really only in the real-time space.
    The normal uses can get by with signals. But I will say, the normal
    uses for computing these days are starting to want the real-time
    powers. :)

    -- Steve


    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2006-07-28 18:49    [W:0.021 / U:1.116 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site