Re: [linux-audio-user] Realtime Audio + Networking

On Tue, 2006-06-06 at 14:31 -0400, Joshua Boyd wrote:
> 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
> program.

Just checking - is the SCHED_FIFO thread ever yielding the CPU? Or is it
just running a loop without ever sleeping or waiting for some lock?

-- 
Lars Luthman - please encrypt any email sent to me if possible
PGP key: http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x04C77E2E
Fingerprint: FCA7 C790 19B9 322D EB7A E1B3 4371 4650 04C7 7E2E