Hi,
I’m trying to identify a performance issue in my zynthian build, I’m using a USB audio interface (actually I tried several interfaces).
I know that the USB stack is CPU consuming, but I am able to run Obxd full voices with Jalv in raspbian strech with desktop without any xrun error.
When I try Obxd with Zynthian OS I get xruns with just 4/5 voices.
Also what are the jack settings? Specifically the Frames/Period in a default desktop setup is quite often it’s set at a much larger value which makes audio processing easier at the expense of high latency.
Can you share a screenshot of top or htop for both situations that you describe? That’ll give a more detailed idea on what is using your CPU at those moments.
I just recalled there are specific buffer sizes and periods that are optimal for USB, specifically for jack. I think this page could be of use to test a few different settings with.
That page would imply that 3 periods would be better than 2, for your sample rate and buffer size.
Yes, I’m using the same jack settings in both environments (same period, buffer size and sample rate).
And yes, I’m testing with the same patches.
Finally I had some time to do another test.
I was able to get an I2S DAC (a suptronics x400 based on a PCM5122) and as I expected the performance is better, I don’t have xruns with NoiseMak3r but there are xruns with Obxd.
The last test that I can do is to change the SD Card, I didn’t check if swap is enabled in the ZynthianOS image but that could be the issue.
Would be great if someone with a similar build (Raspi 3b+ and Usb interface) could confirm that Zynthian image works without xruns when using OBxd and NoiseMak3r with Jalv.
Right. I DISMANTLED my setup to test this magical scenario on my rpi3 B+ using the same patch (StevenGrace/PAD - RandnHold) with obxd on raspbian and zynthian and it xruns like bugger.
note: I’m assuming you’re using the KXStudio repo. It would have been helpful to document ALL the steps when you’re asking people to do testing.
I’m using an old pre build Obxd from zynthian repo
The good thing is this builds have UI, so I can run them using jalv.gtk
I didn’t have time to do more test, but what you can do is to try the jalv from the apt repositories.
Last time I’ve tested I’m pretty sure that I was using the modified version of Jalv which Zynthian OS is using but maybe I’m wrong and the performance problem is related to the increment of buffers in that modified version.