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    SubjectRe: [PATCH] i386: Selectable Frequency of the Timer Interrupt
    --Lee Revell <rlrevell@joe-job.com> wrote (on Tuesday, July 12, 2005 10:24:59 -0400):

    > On Mon, 2005-07-11 at 21:30 -0700, Martin J. Bligh wrote:
    >> Exactly what problems
    >> *does* it cause (in visible effect, not "timers are less granular").
    >> Jittery audio/video? How much worse is it?
    >
    > Yes, exactly. Say you need to deliver a frame of audio or video every
    > 5ms.

    Ummm. that's a 200HZ refresh rate, is it not? That seems unreasonable
    (to a lay-person, as far as video goes).

    > You have a rendering thread and a display thread that communicate
    > via FIFOs. The main thread waits in select() for the next frame to
    > complete rendering or for the deadline to expire. That's next to
    > impossible with HZ=100, because the best you can do is the deadline
    > +-10ms. With HZ=1000 it's no problem.

    So if we have a 50HZ refresh rate, and a HZ rate of 250 or 300, it'll
    work fine then, right? I know that's actually some error in the timers,
    so it may be 2 or 3 ticks, not 1, but if we're running HZ at 5 or 6
    times the frequency of video, presumably that'd still work fine?

    M.

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