[LAU] Ubuntu: changing realtime priority of irqs

From: Atte André Jensen <atte.jensen@email-addr-hidden>
Date: Sat Jul 21 2007 - 15:03:19 EEST

Hi

I trying out ubuntu with ubuntustudio kernel. In debian I always set the
priority of the IRQ's using

chrt -f -p 85 `pidof "IRQ 8"`

However that doesn't work in ubuntu. The reason is that there seems to
be no process named "IRQ 8":

atte@email-addr-hidden:~$ ps aux | grep -i IRQ
root 3 0.0 0.0 0 0 ? SN 13:43 0:00
[ksoftirqd/0]
atte 6274 0.0 0.0 2884 772 pts/0 R+ 13:51 0:00 grep -i
irq

Whereas on debian I would get:

atte@email-addr-hidden:~$ ps aux | grep IRQ
root 18 0.2 0.0 0 0 ? S< 13:34 0:00 [IRQ 9]
root 261 0.0 0.0 0 0 ? S< 13:34 0:00 [IRQ 4]
root 286 0.0 0.0 0 0 ? S< 13:34 0:00 [IRQ
12]
root 300 0.0 0.0 0 0 ? S< 13:34 0:00 [IRQ 1]
root 608 0.0 0.0 0 0 ? S< 13:34 0:00 [IRQ
11]
root 761 0.0 0.0 0 0 ? S< 13:34 0:00 [IRQ
14]
root 787 0.0 0.0 0 0 ? S< 13:34 0:00 [IRQ
15]
root 1592 0.0 0.0 0 0 ? S< 13:34 0:00 [IRQ 8]
root 1593 0.0 0.0 0 0 ? S< 13:34 0:00 [IRQ 7]
root 1683 0.0 0.0 0 0 ? S< 13:34 0:00 [IRQ
10]
atte 4672 0.0 0.0 2848 704 pts/1 R+ 13:41 0:00 grep
IRQ

I suspect it has something to do with "ksoftirqd" which according to the
man page seems to be a daemon handling irqs.

http://tapas.affenbande.org/wordpress/?page_id=40 also doesn't seem to
take ksoftirqd into account.

So my question is: How do I set the priorities in ubuntu? Is it
possible/clever/stupid to get rid og ksoftirqd and get things working
the way I'm used to under debian, and if so how?

-- 
peace, love & harmony
Atte
http://atte.dk       | http://myspace.com/attejensen 
http://anagrammer.dk | http://atte.dk/compositions
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Received on Sat Jul 21 16:15:02 2007

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