INTR_FAST

[Ian Lepore]

On Thu, 2020-08-27 at 19:20 +0530, Kamal R. Prasad wrote:
> Hello,
> 
>  This page
> https://www.freebsd.org/doc/en_US.ISO8859-1/books/arch-handbook/smp-design.html
> 
> says that
> "These interrupt handlers are currently misnamed “fast” interrupt handlers
> since the INTR_FAST flag used in earlier versions of the kernel is used to
> mark these handlers. The only interrupts which currently use these types of
> interrupt handlers are clock interrupts and serial I/O device interrupts."
> 
> I want to use INTR_FAST for my spi controller, but i find that it is not
> defined on freebsd stable11. Is INTR_EXCL related in any way to INTR_FAST?
> if not, how do I setup a fast interrupt handler?
> 
> thanks
> -kamal
> 

An important question here is:  Why do you want to use a filter handler
(formerly called INTR_FAST) instead of a normal threaded handler?  For
something as slow as a SPI bus, I can't imagine you're going to see any
noticible performance difference.

-- Ian