[linux-audio-user] Realtime Audio + Networking

Joshua Boyd jdboyd at jdboyd.net
Tue Jun 6 14:31:40 EDT 2006

On Tue, Jun 06, 2006 at 01:39:31PM -0400, Lee Revell wrote:
> On Tue, 2006-06-06 at 11:10 -0400, Joshua Boyd wrote:
> > I have CONFIG_PREEMPT and CONFIG_PREEMPT_BKL on.  My application runs
> > with SCHED_FIFO and has an elevated priority, but not realtime
> > priority.  When I tried setting it to realtime priority it grinds the
> > networking, control panel, and VGA display applications to a halt. 
> Uhhh, SCHED_FIFO and "realtime priority" are the same thing.
> Can you be more specific?

setpriority(PRIO_PROCESS, 0, -20);

I was under the impression that that set priority to a "realtime"
priority, although rereading the man page I don't see any specific
correlation listed between -20 and realtime.

I also do: sched_setscheduler(0, SCHED_FIFO, &sp);

When I do the setpriority to -20, basically everything other than the
main application grinds to a halt.  If I use -10 instead, other programs
work fine, but networking is then allowed to interfere with the main

Is this specific enough?

I also should probably have mentioned that my application (actually
three programs on one box) is heavily threaded.

Joshua D. Boyd
jdboyd at jdboyd.net

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