[linux-audio-user] MOre realtime!

J M Needham J.M.Needham at bath.ac.uk
Wed Dec 20 05:34:54 EST 2006

Hi all,

So I've just installed Ubuntu 6.09, and followed the instructions on
http://fort2.xdas.com/~kor/oss2jack/install.html to install the
realtime-lsm module and I've added
@audio - rtprio 80
@audio - memlock 500000

to /etc/security/limits.conf and set the realtime mode on Jack. Seems ok,
the only thing is that I can't get below 5.8 ms latency. Jack's behaving
nicely with very few xruns, but won't do any better. The output of the
messages with 32 frames for capture, for example, is:

10:41:35.039 Startup script...
10:41:35.039 artsshell -q terminate
sound server terminated
10:41:35.375 Startup script terminated successfully.
10:41:35.381 JACK is starting...
10:41:35.382 /usr/bin/jackd -R -u -dalsa -dhw:0 -r44100 -p32 -n2 -S
10:41:35.391 JACK was started with PID=5503 (0x157f).
jackd 0.100.0
Copyright 2001-2005 Paul Davis and others.
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details
JACK compiled with System V SHM support.
loading driver ..
apparent rate = 44100
creating alsa driver ... hw:0|hw:0|32|2|44100|0|0|nomon|swmeter|-|16bit
control device hw:0
configuring for 44100Hz, period = 32 frames, buffer = 2 periods
ALSA: cannot set period size to 32 frames for capture
ALSA: cannot configure capture channel
cannot load driver module alsa
10:41:35.502 JACK was stopped successfully.
10:41:37.430 Could not connect to JACK server as client. Please check the
messages window for more info

And I can't see anything of any use in here. Any ideas?


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