Wanted to report a high CPU usage issue that seems to affect only later patch versions of kernel 5.15. Using JACK + Cadence + Carla host and Ardour. CPU usage of the host rises to ~400% or 500% the first time the GUI is opened, no matter what patch is loaded, in both Carla and Ardour. CPU usage drops and Vital remains playable in Ardour once the GUI is closed, but remains high in Carla.
Using Vital 1.0.8 (since 1.5.x currently crashes). OS is Manjaro Linux, x64.
Here are the kernels I'm using:
- LTS kernel: Linux 5.15.72-1-MANJARO:
local/linux515 5.15.72-1
The Linux515 kernel and modules
local/linux515-headers 5.15.72-1
Header files and scripts for building modules for Linux515 kernel
local/linux515-nvidia 515.76-14 (linux515-extramodules)
NVIDIA drivers for linux
local/linux515-virtualbox-host-modules 6.1.38-9 (linux515-extramodules)
Virtualbox host kernel modules for Manjaro Kernel
- My normal kernel: Linux 5.19.14-1-MANJARO #1 SMP PREEMPT Thu Oct 6 07:30:22 UTC 2022 x86_64 GNU/Linux
local/linux519 5.19.14-1
The Linux519 kernel and modules
local/linux519-headers 5.19.14-1
Header files and scripts for building modules for Linux519 kernel
local/linux519-nvidia 515.76-5 (linux519-extramodules)
NVIDIA drivers for linux
local/linux519-virtualbox-host-modules 6.1.38-9 (linux519-extramodules)
Virtualbox host kernel modules for Manjaro Kernel
- Newest kernel: Linux 6.0.0-1-MANJARO #1 SMP PREEMPT_DYNAMIC Mon Oct 3 21:42:15 CEST 2022 x86_64 GNU/Linux
local/linux60 6.0.0-1
The Linux60 kernel and modules
local/linux60-headers 6.0.0-1
Header files and scripts for building modules for Linux60 kernel
local/linux60-nvidia 515.76-1 (linux60-extramodules)
NVIDIA drivers for linux
local/linux60-virtualbox-host-modules 6.1.38-1 (linux60-extramodules)
Virtualbox host kernel modules for Manjaro Kernel
- Other details (inxi):
CPU: 6-core Intel Core i7-10750H (-MT MCP-) speed/min/max: 3071/800/5000 MHz
Kernel: 6.0.0-1-MANJARO x86_64 Up: 41m Mem: 4802.7/31830.9 MiB (15.1%)
Storage: 1.84 TiB (17.0% used) Procs: 342 Shell: Zsh inxi: 3.3.22
A few things I noted:
- Low/high CPU usage: whether CPU usage was high as described above
- GUI delay: whether there was any delay between clicking/typing in the GUI and screen updating. Does not apply to the graphics shown when a note is played, only to things like clicking another tab and waiting for screen to update.
- Black boxes: when closing and reopening the GUI in Carla, sometimes there are black boxes in place of some GUI elements, as shown below. Changing the zoom level to another value and back again fixed this.
- FM Drum Circle crash: sometimes, applying the built-in preset “FM Drum Circle” and playing a note causes both Carla and the host (Carla) to crash.
Results:
- Kernel 5.15 (LTS):
| Issue | LV2 | VST2 | VST3 |
|---|---|---|---|
| High CPU usage | No | No | No |
| Delay in GUI | None | None | Slight |
| Black boxes | Yes | No | Yes |
| FM Drum Circle crash | Yes | No | No |
- Kernel 5.19 (broken one)
| Issue | LV2 | VST2 | VST3 |
|---|---|---|---|
| High CPU usage | Yes | Yes | Yes |
| Delay in GUI | – | – | – |
| Black boxes | – | – | – |
| FM Drum Circle crash | – | – | – |
- Kernel 6.0 (newest)
| Issue | LV2 | VST2 | VST3 |
|---|---|---|---|
| High CPU usage | No | No | No |
| Delay in GUI | None | None | Very slight |
| Black boxes | Yes | No | No |
| FM Drum Circle crash | Yes | No | No |
The issue has only happened for recent patch versions of the 5.19 kernel, and could very well be an NVidia driver issue. I haven’t tested with nouveau since nouveau has issues with my current GPU. Not sure how much of an issue it will be since it looks like it’s working okay with the newer kernel, but thought I should report it.
Cheers,
Sam