16 Jan
2005
16 Jan
'05
10:55 a.m.
Florian Schmidt wrote:
On Sat, 15 Jan 2005 23:04:39 -0500
Eric Dantan Rzewnicki <eric(a)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.