[linux-audio-user] Realtime Audio + Networking

[Lars Luthman]

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
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