> Hello,
>
> I was doing some test on interrupt latency (time from raising an
> interrupt to reading timestamp
> in a handler). I created my own fast handler registered at IRQ32 (
> interrupt is generated by
> the APIC timer on a Ppro 200) that gives me a latency of approx 2300
> nanoseconds
This roughly corresponds to experiences I had with real hardware. I
have PCI cards that generate interrupts. I measure the time that the
INTA# signal is held low. My driver (most sane drivers) clear the IRQ
source pretty early in the ISR. On my P166 Cyrix, the INTA# is about
6uSec.
Under NT, on the exact same computer, with the same hardware in the
same slot, I get numbers more on the order of 60uSec. This is an important
selling point.
-- Steve Williams "The woods are lovely, dark and deep. steve@icarus.com But I have promises to keep, steve@picturel.com and lines to code before I sleep, http://www.picturel.com And lines to code before I sleep."
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