On Wed, 2007-11-28 at 08:12 -0600, K.R. Foley wrote:

John Sigler wrote:

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Hello Steven,

Steven Rostedt wrote:

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John Sigler wrote:

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I need to change the priorities of several soft and hard IRQ handlers.

Namely,

o reduce the prio of "softirq-timer" handler to 10

o reduce the prio of IRQ14 and IRQ15 handlers to 20
   (my flash drives do not support DMA BTW...)

o boost the prio of my I/O boards' IRQ handlers to 60
   (there can be 1 or 2 boards, the driver is a kernel module
    which is loaded after the system has booted.)

I've written a short program that calls
   sched_setscheduler(pid, SCHED_FIFO, &param);
with the appropriate pid, which I look up using ps -ef

Look for the program "chrt". It does this for you. This program is
available in all major distributions of Linux.

Thanks for the tip.

For the record, I found schedutils on Robert Love's page:

http://rlove.org/
http://rlove.org/misc/schedutils-1.5.0.tar.gz

However, I had already solved that part of the problem with a
program of my own.

My real problem is: the IRQ handlers for the I/O boards are
only instantiated when the kernel module is inserted. How do
I /reliably/ determine their pid?

What about something like:
chrt -f -p 99 `/sbin/pidof 'IRQ 8'`

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Keep in mind that if you are on a shared IRQ line, you will be boosting
the priority of other interrupts as well.

Sven