[linux-audio-user] realtime-preempt-2.6.11-rc1-V0.7.35-01

[Eric Dantan Rzewnicki]

Florian Schmidt wrote:
> On Sat, 15 Jan 2005 23:04:39 -0500
> Eric Dantan Rzewnicki <eric at zhevny.com> wrote:
> do you compile it as "Preemptible Kernel (Low-Latency Desktop)" or as
> "Complete Preemption (Real-Time)"?

I went for Complete real-time on this build.

> In the former case, just making all irq handlers threaded except for the
> soundcard irq handler should give pretty good results already (also run
> jack at a prio of 60 or 70 in this case). For this the "threaded irq
> handlers" section on the page you quoted should be accurate. 

How do I set jackd's priority?

> In the latter case all irq handlers are threaded by design, so in this
> case you need to make sure that our soundcard irq is the highest prio
> irq handler in the system. Make the soundcard irq handler sched_fifo
> with prio 98 instead of unthreading it. I always have the keyboard irq
> handler at prio 99, so magic sysrq works even in the worst cases (i
> haven't seen negative effects on jack operation yet).

There is a link on the wiki about setting irq priorities, but it seems 
to be broken. How do I set these? and how do I set SCHED_FIFO for an irq 
handler?

> The other /proc and /sys stuff is mostly important for debugging. 
> Also when in doubt consult the help texts of the kernel configuration
> options.. They should have the relevant info, too.

Thanks Florian.

I'll try building with the Pre-emptible, low-latency desktop option 
today as well.

-ERic Rz.