I was stupidly sure I was running a lowlatency kernel
just because my
/proc/sys/kernel/lowlatency was set to 1.
Then you are running a lowlat enabled kernel...
I used to start jack with something like
$: jackd -R -d alsa -d opl3sa2 -r 44100
and I was surprised by the great number of xruns. Now I tried "jackstart" as
root and... what? This kernel does not have capabilities enabled?!
[MUNCH]
Kernel 2.4.20-ck2 (almost: it's a 2.4.20 vanilla
with Con Koliva's lowlatency,
preemtpible and arcangeli's VM patches)
This combination does not include the capabilities patch (AFAIK). The
capabilities patch does not affect the latency, only the ability to run
applications with realtime priority as a non-root user (using jackstart
or givertcap, for example).
-- Fernando