lkml.org 
[lkml]   [2004]   [Oct]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [patch] Real-Time Preemption, -VP-2.6.9-rc4-mm1-U0

* Florian Schmidt <mista.tapas@gmx.net> wrote:

> Cool :)
>
> Say, does it still apply that one should not use unthreaded IRQ
> handlers for all IRQ's when using PREEMPT_REALTIME (Except maybe for
> the keyboard)?

yes - and this kernel simply does not allow the un-threading of
interrupt handlers anymore, so you cannot accidentally misconfigure it.
(Not even the keyboard interrupt is an exception, it would have
lock-ripple-effects elsewhere.)

so the preferred (and only) interface to mark interrupts 'high prio' is
via process priorities. Starting from the -U1 kernel it will be possible
to do this:

chrt -f 60 -p `ps -C 'IRQ:1' -o pid=`
chrt -f 60 -p `ps -C 'IRQ:8' -o pid=`

this sets the keyboard and the RT-timer interrupt to FIFO:60.

In -U0 this is not possible because 'ps -C' does not handle kernel
threads with a space in their name. So there you'd need some wacky thing
like:

chrt -f 60 -p `ps ax -o pid= -o comm= | grep "IRQ 1$" | cut -dI -f1`
chrt -f 60 -p `ps ax -o pid= -o comm= | grep "IRQ 8$" | cut -dI -f1`

(someone should fix procps - or does it intentionally break with
whitespace command-strings?)

Ingo
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 14:07    [W:0.601 / U:6.884 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site