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    SubjectRe: [PATCH] HZ change for ix86
    On Sat, Jan 09, 1999 at 07:05:16PM -0500, Richard B. Johnson wrote:
    > > > There seems to be a general misinformation about what the HZ value is.
    > > > I will "simplicate and add lightness".
    > >
    > > still darkness here....
    > >
    > > > However, if your code is doing:
    > > >
    > > > UncompressFonts(...........);
    > > > ReadAudioFromDsp(...........);
    > > > ConvolveImageData(..........);
    > > >
    > > > you don't want the CPU taken away until you are done.
    > >
    > > We can't prevent the kernel from taking away the CPU - and a higher HZ value
    > > helps us get back the CPU as soon as possible.
    >
    > If we don't do blocking system calls, we don't lose the CPU until our
    > time-slice is up.
    >
    > Once you lose the CPU, you may lose it for N time slices because there
    > are N computable tasks that will get it before you get it back. This is a
    > multitasking operating system with many more tasks than just yours. You
    > get it CPU back when it's your turn, not the next timer-tick.
    >
    > If N tasks are CPU bound, you sure want a long time-slice before the
    > CPU gets stolen from you.

    Why? Each of the N processes gets the 1/N of the CPU - wheter there are
    long or short timeslices. If you have the CPU for long time, you'll miss
    it for long time...

    > > > doesn't produce visual effects. The higher the HZ value, the more
    > > > often the CPU gets stolen from the interactive user.
    > >
    > > Why is that a problem? Here is an example:
    > > You earn 1000$ a month. Your boss decides to pay you not monthly but weekly,
    > > and you begin to complain that you earn only 250$.
    >
    > Not accurate.

    I think so.

    Anybody, who agrees with Johnson?

    --
    [:)]---------------------------
    [:)] Horvath Karoly Zoltan / Technical University of Budapest
    [:)] rh@the.rulez.org / an active member of AC Studio & Live
    [:)]-------------------------

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