Re: i8259 and IO-APIC

[Alan Cox]

On Mon, 2002-05-27 at 15:35, Terje Eggestad wrote:
> Do you got any numbers that state that it's processing overhead, and not
> HW latency that is the bulk of interrupt service time? Just curious,
> I've been looking and can't find this "perceived fact" backed up by
> facts anywhere. 

It depends what the interrupt actually does. What I was saying is that
the processing overhead is what hurts not the latency. If you think
about a continual stream of events latency on the busses effectively
skews the delivery time of the interrupt but not the rate of processing.

> BTW: according to "IA-32 Intel Arch. Software Developer's Man Vol 3"
> both P3 and P4 the APIC bus is three wire, two data and one clock.