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    SubjectRe: Can't sleep less than 20 ms
    Matti Aarnio wrote:
    > > x86 also takes 10 or more microseconds to service an interrupt (it is
    > > said because of motherboards not the CPU itself).
    >
    > How long IRQ processing takes *does* depend upon used chips.
    > When the IRQ-controller is in modern core-logic chipsets, it
    > does not need to behave like its ancient ISA-bus-bound
    > precursors.

    I would like this to be so, but I've heard that current motherboard
    designs prevent the core-logic chipsets and the processor from servicing
    interrupts at full speed.

    I don't have figures though so I can't argue this point.

    > > I'd rather see:
    > >
    > > - slow HZ -- low interrupt load
    > > - accurate timers on demand
    > > - *precise* timing with accuracy of hardware
    >
    > RTC based interrupts ? Highly accurate periodic interrupts,
    > not re-sceduling based "regular by luck"...

    I'd like "regular by design".

    Note that RTC interrupts are just as inaccurate for user space apps
    than 8253-based accurate timers -- the scheduling overhead and lack of
    guarantee is still present.

    -- Jamie


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