[linux-audio-user] -rt IRQ handler priorities

[Lee Revell]

On Tue, 2006-05-09 at 15:45 -0700, Kjetil S. Matheussen wrote:
> > Hmm, it sounds like a solution could be to separate timers that just
> > wake up a process from ones that do actual work and run them in separate
> > kernel threads.
> >
> 
> I don't understand why you want that. To me (which
> knows about nothing about how the kernel works), the solution to 
> the problem is crystal clear: The softirq timer needs to have the highest 
> priority, and the only thing the sofirq timer threads does is to
> make sure threads that should be woken up are put into some kernel
> schedule queue somehow. I don't understand why the softirq timer threads 
> should cause any latency problems, what does it do except scheduling 
> waiting threads?
> 

Well as you have seen the softirq timer thread apparently does route
cache flushing and a bunch of other things we don't want it to do.  I
was under the impression these were already done by separate threads.

I think we are in agreement.  I have to double check how it works in -rt
- I've been running mainline lately which still has a single ksoftirqd
process.

Lee