Re: INTC issue

Yoshihiro Shimoda
2009-02-25T04:11:40Z

Hi Magnus-san,

Magnus Damm wrote:
> I agree that the overhead is increased a bit, but 100% working
> interrupt masking is more important than performance. This only
> affects some processor types though, so hopefully future processors
> allow us to mask interrupts in a more fine-grained fashion. For
> instance, SuperH Mobile devices such as sh7722 and sh7723 does not
> require any fixes like this. =)

I think so too. :)

> Also, regarding performance, out cache footprint becomes slightly
> smaller with a single interrupt for multiple vectors. That may
> compensate a bit for the added overhead.

I see! I did not think of cache.

> Cool. If you want to use a single interrupt but keep the overhead to a
> minimum I recommend a change similar to my recent sh-rtc patch. It is
> using a single shared interrupt handler - like the
> sci_mpxed_interrupt(). I think such a strategy may be more efficient
> than using multiple shared interrupt handlers.

I refer to your sh-rtc patch and I will modify DMAC driver.

Thank you very much for your help!