> > > Does anyone know a good way to test the irq handling speed?
> >
> > Does it make sense to run a userland benchmark program to measure
> > irq_entry speed?
> 
> I was wondering if some kind of heavy disk read/write etc might exercise irq 
> handling, but then you might find that it gets hidden by the vm system...
> 

Heavy use of the printer port in polled mode does it for me... 
Particularly when printing somehting like postscript via a filter to an 
inkjet. ( >1000 interrupts per second, IIRC).