[LAU] a lot of xruns after upgrading from ubuntu 8.04 to, 10.04

[Jeremy Jongepier]

On 02/02/2011 08:29 PM, Kim Cascone wrote:
> I've also been having some issues with xruns (mostly while using the
> zynaddsubfx synth) and have been fiddling with my Jack settings to see
> if I can minimize them
>

Hello Kim,

Try Yoshimi. ZASFX is notorious for generating xruns.

> current settings: RT=true; Priority: 89; Frames: 1024; SR: 44kHz,
> Periods/Buffer: 3; and my latency is 69.7mS
>

89 is too high, it's better to run JACK with a prio around 70. Now 
JACK's watchdog thread I running prio 99 which might cause problems with 
other processes running that prio.

> -- I'm using the 2.6.36-3.dmz.2-liquorix-686 kernel
> ---------------------------------------------------------------
> -- another weird anomaly is that I get clicks from the zynaddsubfx synth
> engine when pressing more than one or two keys at once or when going
> from one key to another -- mostly heard on pads...this happens
> intermittently and doesn't happen all the time
>

Yoshimi doesn't suffer from this issue either.

> settings in my limits.conf file:
> ==================================
>
> /etc/security/limits.conf
> @kim - rtprio 99
> @kim - memlock unlimited
>
>
>
> settings in my audio.conf file:
> ================================
>
> /etc/security/limits.d/audio.conf
> the same parameters are # commented out in the 'audio.conf' file
>
> do they need to be uncommented out?
> not sure why there exist two places and whether having one location is
> sufficient...?
>

They should be commented out in your /etc/security/limits.conf file (or 
don't exist at all in that file) but exist in your 
/etc/security/limits.d/audio.conf file.
The lines used to get added to the limits.conf file but recently a lot 
of distro's moved to adding them to the audio.conf file.

>
> is there a thread or page where Jackd optimization is discussed in detail?
> I've read the Jack FAQ http://jackaudio.org/faq
>
> but it would be helpful if there was something outlining how to adjust
> all the various params to minimize xruns for various work environments...

JACK parameters alone won't help you set up an xrun free audio 
environment, it takes some more: 
http://wiki.linuxmusicians.com/doku.php?id=system_configuration (that 
wiki page is continously being updated, so if it contains any errors 
please let me know)

Best,

Jeremy