Re: interrupt latency

Etienne Lorrain (lorrain@fb.sony.de)
Tue, 11 Aug 1998 15:17:03 +0001


> I reall wish this wasn't the case because I would dearly
> love to be able to have interrupt latency as a benchmark
> test in lmbench. Are you sure there is no way to do this
> in software? What if you had some way to generate interrupts
> essentially continuously?

Hi,

What you could do is to look at how drivers auto-detect
the interrupts of their hardware, there is often few bits
to change in I/O space to trigger an IRQ (different for
each video/serial/IDE... boards and ISA/PCI bus).

So unload the module managing the card, setup the interrupt
handler, store the time from the Pentium timestamp,
generate the IRQ by changing the special I/O bits, store
the time in the interrupt handler, clean the hardware
and reload the module.

Have fun,
Etienne.

--
-- The world belong to its organizer.

- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.altern.org/andrebalsa/doc/lkml-faq.html