Messages in this thread | | | Date | Fri, 9 Jul 1999 22:45:06 +0200 | From | Jamie Lokier <> | Subject | Re: Can't sleep less than 20 ms |
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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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