[linux-audio-user] Re: Realtime Kernel Slows My Clock

[Florian Schmidt]

On Tue, 07 Feb 2006 19:43:18 -0500
Lee Revell <rlrevell at joe-job.com> wrote:

> On Tue, 2006-02-07 at 18:46 -0500, Chuck Martin wrote:
> > On Tue, Feb 07, 2006 at 05:22:23PM -0500, Lee Revell rlrevell-at-joe-job.com |LAU| wrote:
> > 
> > > > Do you have the problem with 2.6.15.x (the non-realtime kernel)?
> > 
> > No.  I've used 2.6.15, 2.6.15.1, and 2.6.15.2 with no problems.
> > 
> > > Hmm, IIRC this might have been related to the softirq timer thread being
> > > preempted - try setting it to the maximum RT priorirty (99).
> > 
> > How is that done?  (This is on Slackware 10.0).
> > 
> 
> Not sure, it's in the list archive.

Hi,

i think the kernel thread in question is "softirq-timer/0". It is kinda
resistant against the usual 

chrt -f -p `pidof "softirq-timer/0"` 

but something like this works:

 /usr/bin/chrt -f -p 96 `/usr/bin/getpid.sh "softirq-timer/0"`

where getpid.sh looks like this:


------------------snip
#! /bin/sh

# Uncomment the next line for testing
#set -x

if [ $# -ne 1 ]; then
    echo "Usage: $0 prog_regexp";
    exit 1;
fi

ps auxc|grep ${1}|sed 's/^[a-zA-Z]* *\([0-9]*\).*$/\1/'
------------------snap

Provided by a kind soul in #lad. I forgot who sorry :(

I just don't know whether this is a cure for the problem at hand. I
haven't read the whole thread.

Flo

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