[PD-dev] jack driver issues with 0.43

Roman Haefeli reduzent at gmail.com
Tue Feb 28 20:55:21 CET 2012


Hi again

Is anyone else experiencing freezes due to this? Often with jack, when
turning DSP off, Pd hangs and I get the watchdog messages, but no crash,
Pd is just frozen. Is there any chance of getting back the old
behaviour, that didn't spawn a new thread whenever DSP is turned on?

Roman 

On Tue, 2012-02-07 at 10:49 +0100, Roman Haefeli wrote:
> Hi all
> 
> When employing dynamic patching, in particular when doing dynamic
> patching with ~-objects, I found that drop-out time can be greatly
> reduced by turning dsp off during dynamic creation time. I used to turn
> dsp off and on in 0 logical time a lot in my patches and it never seemed
> an issue.
> 
> Recently, I found that when doing so it causes a drop-out, no matter if
> there is dynamic patching going on or not. I figured out, that this
> happens only when Pd is using jack as the audio back-end. In gdb, I
> noticed that when ever I turn dsp off, I get those messages:
> 
> [Thread 0xb3065b70 (LWP 11244) exited]
> [Thread 0xb7f60b70 (LWP 11243) exited]
> [Thread 0xb7fe1b70 (LWP 11242) exited]
> 
> When turning dsp on again, I get:
> 
> [New Thread 0xb7fe1b70 (LWP 11250)]
> [New Thread 0xb7f60b70 (LWP 11251)]
> [New Thread 0xb3065b70 (LWP 11252)]
> 
> It seems, that since 0.43 - when using jack - turning dsp off and on
> cannot be done "silently" anymore. For me, this has a few implications:
> 
> * I certainly get a drop-out in the audio stream. Starting and stopping
> dsp costs a lot of time now.
> 
> * The jack-client 'pure_data_X' disappears when turning dsp off and thus
> it looses all hand-made connections to other applications.
> 
> * Often, Pd hangs after a few cycles of turning dsp off/on. Pd-gui
> doesn't respond on any input and I see the 'watchdog signaling Pd'
> message appearing.
> 
> Personally, I find the old no-thread-spawning-on-dsp-on implementation
> much friendlier in many ways, but to me most importantly, it was able to
> avoid drop-outs when turning dsp off and on in 0 logical time. 
> 
> What do others thing, what is their experience? Is there any chance of
> going back to the old way of using Pd with jack?
> 
> BTW: Everything works still nice with ALSA.
> 
> Roman
> 
> 





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