[PlanetCCRMA] Jack Realtime Problem, xruns

[Fernando Lopez-Lezcano]

On Wed, 2007-02-21 at 20:19 +0100, Nils Winkler wrote:
> I'm having problems running Jack, I'm getting lots of xruns. Hardware
> should be sufficient, it's a LG W1 notebook with 2 GB RAM and a Core 2
> Duo with 2 GHz. Fedora Core 6 with the Planet CCRMA repos enabled. The
> versions of Jack installed are: qjackctl-0.2.20-7.fc6 and
> jack-audio-connection-kit-0.102.20-3.fc6, both probably from the Extras
> repo.
> 
> The xruns start showing up before I even attach an application to Jack,
> something feels very wrong here.
> 
> When I start qjackctl and go to setup, the Realtime checkbox is checked,
> but greyed out, so I can't change it. When starting Jack, the "-R"
> switch is passed to jackd, but the "RT" LED in the qjackctl display is
> dimmed, looks like Realtime is not really working. I did the recommended
> changes in /etc/security/limits.conf:
> 
> *               -       rtprio          99
> *               -       nice            -10
> *               -       memlock         4000000
> 
> and rebooted, but the problem is still there - before the changes, it
> didn't even allow me to start jackd due to missing permissions. Is there
> something I'm missing? Any feedback is appreciated.

Try increasing the number of periods to, say, 3 ("-n 3") or more and
decreasing the period size to 1024 or 512. 

That sometimes helps with soundcards that are not really good. 

-- Fernando


> Here's the log output from Jack:
> 
> 20:04:33.856 Patchbay deactivated.
> 20:04:33.876 Statistics reset.
> 20:04:33.912 MIDI connection graph change.
> 20:04:34.081 MIDI connection change.
> 20:04:46.148 Startup script...
> 20:04:46.148 artsshell -q terminate
> 20:04:46.464 Startup script terminated with exit status=256.
> 20:04:46.464 JACK is starting...
> 20:04:46.464 jackd -R -dalsa -r48000 -p4096 -n2 -D -Chw:0 -Phw:0
> 20:04:46.483 JACK was started with PID=14619 (0x391b).
> jackd 0.102.20
> Copyright 2001-2005 Paul Davis and others.
> jackd comes with ABSOLUTELY NO WARRANTY
> 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 = 48000
> creating alsa driver ...
> hw:0|hw:0|4096|2|48000|0|0|nomon|swmeter|-|32bit
> control device hw:0
> configuring for 48000Hz, period = 4096 frames, buffer = 2 periods
> ALSA: final selected sample format for capture: 32bit little-endian
> ALSA: use 2 periods for capture
> ALSA: final selected sample format for playback: 32bit little-endian
> ALSA: use 2 periods for playback
> **** alsa_pcm: xrun of at least 0.031 msecs
> **** alsa_pcm: xrun of at least 0.060 msecs
> **** alsa_pcm: xrun of at least 0.031 msecs
> **** alsa_pcm: xrun of at least 0.035 msecs
> **** alsa_pcm: xrun of at least 0.026 msecs
> **** alsa_pcm: xrun of at least 0.032 msecs
> **** alsa_pcm: xrun of at least 0.032 msecs
> 20:04:48.497 Server configuration saved to "/home/nils/.jackdrc".
> 20:04:48.501 Statistics reset.
> 20:04:48.823 Client activated.
> 20:04:48.826 Audio connection change.
> 20:04:48.835 Audio connection graph change.
> **** alsa_pcm: xrun of at least 0.074 msecs
> 20:04:48.939 XRUN callback (1).
> **** alsa_pcm: xrun of at least 0.033 msecs
> **** alsa_pcm: xrun of at least 0.040 msecs
> **** alsa_pcm: xrun of at least 0.041 msecs
> **** alsa_pcm: xrun of at least 0.032 msecs
> **** alsa_pcm: xrun of at least 0.039 msecs
> **** alsa_pcm: xrun of at least 0.032 msecs
> 20:04:50.841 XRUN callback (6 skipped).
> **** alsa_pcm: xrun of at least 0.027 msecs
> **** alsa_pcm: xrun of at least 0.043 msecs
> **** alsa_pcm: xrun of at least 0.033 msecs
> 20:04:52.280 Client deactivated.
> 20:04:52.283 JACK is stopping...
> jack main caught signal 15
> no message buffer overruns
> 20:04:52.502 JACK was stopped successfully.
> --
> ==================================
> nils@nilswinkler.com
> 
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