Unusually low performance of plugin in ElkPi

Hi there, I recently came across some seemingly random slownesses with a synth plugin I’m running on ElkPi. What I observer is that the Pi gets very busy and then there’s an enormous latency in the notes my synth plays (in the range of seconds). Sometimes after restarting the plugin the problem goes away, but sometimes it is there from start. I don’t think the issue should be in the plugin itself because it used to work fine until very recently (with same compiled version) and also it works fine on desktop machine. There are a number of things I want to test to be more sure about what’s going on, but one thing that surprises me is that I see a lot of sushi processes on the pi when I run htop. I only load a single plugin, but I see ~15 sushi processes. Is that normal?

Thanks in advance!

Hi @frederic,
are you sure those are not just different threads for a single SUSHI process?

Is this Pi3 or Pi4? My first suspect will be overheating issues on the Pi4 which trigger the CPU throttling. Try to see if setting the CPU to min. freq using elk_system_utils leads you to a more stable situation - if that’s the case, the solution might just be to use a more powerful heatsink / vent.

Hi @Stefano, thanks for the answer.
It is probably threads of a single SUSHI process, but it looks weird that there are so many. I’m in Pi4 so it could be the temperature thing. If I remember correctly the measurements were between 50º and 60º (I use an aluminium heatsink, and the elk board is separated ~2 cm without touching parts). I’ll try with the CPU freq setting and see if it is more stable.

Hi frederic.

I´m just at the point of buying a Pi4 and I´m concerned about potential temperature issues. Did you have a diagnostic of your issue? Was if finally because of heating/temperature?


Hi Sedaxel,
No, my issues were not because of temperature but because of issues with the MIDI interface I was using and bad RT programming on my side. Elsewhere in this forum there is a post on fans and other methods of cooling the RPI4. I show there the one I use and it works fine.


Thank you so much, mate!