On Sun, 16 Jan 2005 20:28:24 +0100, Florian Schmidt <mista.tapas@email-addr-hidden> wrote:
>
> > There is a link on the wiki about setting irq priorities, but it seems
> > to be broken. How do I set these? and how do I set SCHED_FIFO for an irq
> > handler?
>
> Hmm, "irq priorities" are something different from "irq handler
> priorities". The former refers to the priorities on the interrupt
> controller. Usually messing with these is not needed, especially on RP
> kernels, as the top level irq handler routines are very short.
>
> What we want to control is the priority of the bottom half irq handler
> which is doing the grunt work. For this, the chrt utility from the
> schedutils package is useful..
>
> chrt -f -p 99 `pidof "IRQ 5"`
>
> for example, makes the bottom half irq handler for IRQ 5 run SCHED_FIFO
> with a priority of 99. Inspect the output of
>
> cat /proc/interrupts
>
> to see which irq number corresponds to which device..
>
> Use
>
> chrt -p `pidof "IRQ 5"`
>
> to inspect the scheduler classes and priorities for irq's..
>
This is essentially what Rui's rtirq script does, based on some user input.
Florian, I noticed your wiki was locked. It would be great to get some
of the up to date info up somewhere (mostly the RT preempt stuff). I
was about 1/2 through writing a gentoo how-to when I realized it was
much more generic (and most of this stuff isnt in portage anyway). Is
there a way to sey up the wiki with a generic lad password? The way
the RT stuff (and the kernel in general) has changed and evolved in
the last 6 months seems to say we need a doc for this stuff thats
really living.
Received on Mon Jan 17 00:15:13 2005
This archive was generated by hypermail 2.1.8 : Mon Jan 17 2005 - 00:15:14 EET