[PD] Latency under Linux/Jack (again...)

Pedro Lopes pedro.lopes at ist.utl.pt
Tue Oct 12 16:33:04 CEST 2010

If you start pd in sudo, you have to connect to jack in sudo mode. Thus
start jack in sudo (or gksudo for qjackctl).

I advise to use an rt kernel too. See documentation of Ubuntu Studio.

On Tue, Oct 12, 2010 at 3:27 PM, Raphael Raccuia <
rafael.raccuia at blindekinder.com> wrote:

> Hi list,
> I tested Pd rt as I need low latency for a performance next week...
> It seems -rt flag doesn't have any effect. I measured Pd latency with
> jdelay, and always get 640 (@48000), so about 13ms (pd only)... lower I
> set buffer in jack (no less than 256), more DIO errors I get... and
> there are a lot! This setting works great with many application
> (Ardour...), with about 10ms (~15 really). So I would have ~25ms, which
> is acceptable, but too many DIO errors!
> -what is -defeatrt setting? (I tried 0 and 1, no change)
> -why is -rt flag without effect?
> -tried nosleep, no change...
> I also tried to start pd in root (sudo)...
> It says:
> priority 8 scheduling enabled.
> priority 6 scheduling enabled.
> (which I normally don't have)
> but unfortunately can't connect to jack (state 17)
> thank's for your help
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Pedro Lopes (ongoing MSc)
contact: pedro.lopes at ist.utl.pt
website: http://web.ist.utl.pt/Pedro.Lopes
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