[PD] pd clicking with jack/linux

Atte André Jensen atte.jensen at gmail.com
Tue Jul 1 13:09:49 CEST 2008

patrick wrote:
> hi,

Hi. Thanks for the reply!

Basically I think my problems came from using array (and not table) to 
store a sample. Pd gave DIO errors when switching to the window 
containing the patch. Is this normal, and is there a way to avoid it, 
for instance running the gui in a separate thread?

After switching to table (with very little testing, though) everything 
seems to work just fine :-)

So the rest of this mail is releated to a patch using the problematic 

> i don't use pd-extended, but i think it's almost the same. the only 
> option missing is: -nosleep (useful for dual-core).

I'm on a single core, so I guess -nosleep doesn't matter, right?

> so be sure in qjackctl - setup:
> Realtime
> Periods/Buffer: 2
> Sample Rate: 44100 (or more)
> Frames/Period: 256 (i am running at 64 without glitches)

Something like that, although periods/buffer is 3 here (seems to work 
better in general with my sound card).

> then for pd:
> pd -rt -jack -r 44100 -nosleep -audiobuf 256 -channels 16 -alsamidi 
> -mididev 1 etc...


1) "pd -?" says -audiobuf is in ms, so 256 wouldn't make sense, or...?

2) I thought that jack clients automatically got the same buffer size as 
jack, which means that is doesn't make sense (or any difference) to 
specify that for the client. Same with -rt, I thought that clients 
"enherited" the realtime priority from jack...

> and finally, be sure to edit /etc/security/limits.conf:
> @audio          -       rtprio          99
> @audio          -       memlock         unlimited
> @audio          -       nice            -20
> and of course, add yourself to audio group (reboot to be sure). let us 
> know.

I already had that (or something *very* similar).

> ah yes, a long time ago i was using icewm, because gnome was causing 
> glitches in pd. but now it seems ok here.

I now tried with openbox (lighter than icewm) and the problem is the same.

peace, love & harmony

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