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QjackCtl Graph Window laggy with DrumGizmo in Ardour

When using the graph window to make connections it is usually responsive.

I loaded DrumGizmo into Ardour and this creates a lot of input/output ports and wires between them. The graph window is now unusably laggy. There is a delay between dragging a wire and the wire appearing. This gets progressively worse the higher the zoom setting. The more I zoom in the more laggy the graph window becomes.

I'm using Arch linux and QjackCtl 0.9.2

rncbc's picture

please resort to the old Connections window, if you please.

when there's lots and lots of ports or whatever, the Graph won't be really manageable or useful anyway. ;)


Thanks for your reply.

I like the Graph window in QjackCtl because I can change the colours of ports and use JACK pretty-names.

When I was investigating this I tried the patchbay in Carla at the same time as QjackCtl and the Carla patchbay can handle DrumGizmo without responsiveness decreasing. I also have had big projects in Carla e.g. 30 instances of a synth where QjackCtl was not laggy.

But yes, I can find workarounds.


I have the same problem, the Graph becomes laggy also when you open an Ardour project with few tracks. In the previous versions (like 1 year to few months ago) of Qjackctl i didn't notice this problem.
Hope this will be solved in the future.
Thank you.

rncbc's picture

hi, when you say that the Graph is lagging, may I ask what you really mean?

I've been testing--yes "testing", just because ardour is not quite my piece of cake, I think you understand--with several dozens of tracks on ardour6.6 and, quite frankly, I'm don't get what you're meaning :)

care to give some more details on your machine, setup and environment?
really appreciate that.

I tried on 2 different machines with very different HW on them, cheap Intel CPU vs expensive Intel CPU, Intel GPU vs Nvidia with proprietary drivers, no difference. The problem seems to be the presence of "curved" connections, like when you have more output connections coming back to inputs in the same client, like Ardour. When you have "straight" connections there is no noticeable lag, like you could have with a simple Carla setup, Ex: Synth > FX > Mixer > System Out.

rncbc's picture

care to tell what exactly you mean with "lagging" or "noticeable lag" ? is it about view refresh? delay in selecting or moving nodes? making connections or disconnections? what and when exactly, please.


By lag i mean an increased delay between the mouse click or drag and the movement of graph elements. For example when moving clients, selecting, creating or deleting connections, the delay seems directly proportional to the number of "curved" connections present in the client. If i disconnect all the "curved" connections the interaction with that client in the Graph becomes snappier again.
Thanks for taking time to look into this.

rncbc's picture

I see... but it also gets better on zooming out and worse on zooming in...

well, if you can't live with that, for the moment then my first reply still applies ;)


rncbc's picture

hi there, good news:

been listening to your concerns and then, duly investigated the wth was going on in there...

as it happens, in the long run and finally reaching the bottom line, just found that too-much eye-candy was causing this and some graphical diabetes type IV, perhaps (my nomenclature) ;)...

all is now mitigated on qjackctl >=

just don't worry too much about, uh, connection lines not having a dang drop-shadow effect anymore. good riddance!

[UPDATE:] forget the last line, drop-shadow eye-candy++ is back to connection lines. and the laggy behavior seems to be gone too.

please test && tell, thanks.


Thank you very much. :D


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