Cinnamon process high CPU usage during idle

[GitGrove]

Distribution

Linux Mint 22.1 Cinnamon

Package version

6.4.8

Graphics hardware in use

NVIDIA Corporation AD106M [GeForce RTX 4070 Max-Q / Mobile]

Frequency

Always

Bug description

Beginning last week, my laptop fan started blowing intensely and battery drained fast even when I wasn't running any programs. I realized that the Cinnamon process has been using an unusual amount of CPU power across multiple cores when idle which never used to be the case. I've tried to debug on my own (see below) but think Cinnamon itself might be either the cause or the key to figuring out what's going on. Any help is appreciated as I can't reliably use Linux anymore while mobile on battery.

Steps to reproduce

I'm just booting into Linux Mint and it's happening.

Expected behavior

I expect Linux Mint Cinnamon not to drain my battery with high CPU usage when idle.

Additional information

I've tried several older Linux kernel versions including some OEM versions and haven't seen much change so I don't think it's a kernel issue. I first encountered this when running my onboard AMD iGPU, but when I switched to the NVIDIA driver, nothing changed regarding Cinnamon's unusual CPU usage. Cinnamon's memory usage is normal.

[QmF0bWFu]

I can confirm that behavior. It started a few days ago.

OS: Linux Mint 22.1 x86_64
Kernel: 6.14.0-27-generic
DE: Cinnamon 6.4.8
WM: Mutter (Muffin)
CPU: AMD Ryzen 5 7530U with Radeon Graphics (12)
GPU: AMD ATI 04:00.0 Barcelo

[GitGrove]

I tried a few of tricks to restart Cinnamon including ctrl + alt + esc and alt+f2 -> r from the desktop and killall -HUP cinnamon from the command line but neither make a dent in the high CPU usage. The interesting thing is that my system was upgraded to Cinnamon 6.4.8 several months ago, but the high CPU usage issue is only about a week old, so it might be a dependency that's making Cinnamon misbehave.

[GitGrove]

Okay I might have narrowed it down to... drum roll please: The multicore-sys-monitor applet that you see a screenshot of above. Here's the relevant issue. I'm not closing this yet as I'd like to spend a couple of days verifying, but for anyone else seeing this, maybe disable some applets and see what happens.

[QmF0bWFu]

Yes, that is the cause of it. I also had the Multi-Core System Monitor installed.
When I removed it, everything went back to normal. CPU usage went down and the laptop fan is not spinning anymore on idle.
I remember that this applet got updates a few days ago when the issues started.
Thank you for the investigation!

[Bazzilla]

Hi!
I face the same issue without having multicore-sys-monitor installed.

OS: Linux Mint 22.1 x86_64
Kernel: 6.8.0-78-generic
DE: Cinnamon 6.4.8
WM: Mutter (Muffin)
CPU: Intel i5-8250U (8) @ 3.400GHz
GPU: Intel UHD Graphics 620

[jkirk]

I also have the same problem: high cpu usage (30% on a 10 core system) after upgrade from Debian/bookworm to Debian/trixie:

OS: Debian/trixie
Kernel: 6.12.95+deb13-amd64
DE: Cinnamon 6.4.10
WM: Mutter (Muffin)
CPU: Intel i7-1355U (10) @ 3.400GHz
GPU: Intel Raptor Lake-P [Iris Xe Graphics]

multicore-sys-monitor is not installed.

Found this: https://forums.linuxmint.com/viewtopic.php?t=456282, but I have no /etc/X11/xorg.conf.d

After some investigation I found out that I was running software rendering:

❯ glxinfo -B | egrep -i 'renderer|opengl version|direct rendering'
direct rendering: Yes
Extended renderer info (GLX_MESA_query_renderer):
OpenGL renderer string: llvmpipe (LLVM 19.1.7, 256 bits)
OpenGL version string: 4.5 (Compatibility Profile) Mesa 25.0.7-2+deb13u1

❯ inxi -G    
Graphics:
  Device-1: Intel Raptor Lake-P [Iris Xe Graphics] driver: i915 v: kernel
  Device-2: Bison Integrated RGB Camera driver: uvcvideo type: USB
  Display: x11 server: X.Org v: 21.1.16 driver: X: loaded: modesetting
    unloaded: fbdev,vesa dri: swrast gpu: i915 resolution: 1: 1920x1080~60Hz
    2: 1920x1080~60Hz 3: 1920x1200~60Hz
  API: EGL v: 1.5 drivers: kms_swrast,swrast
    platforms: gbm,x11,surfaceless,device
  API: OpenGL v: 4.5 vendor: mesa v: 25.0.7-2+deb13u1 renderer: llvmpipe
    (LLVM 19.1.7 256 bits)
  API: Vulkan v: 1.4.309 drivers: llvmpipe surfaces: xcb,xlib
  Info: Tools: api: eglinfo, glxinfo, vulkaninfo gpu: gputop,
    intel_gpu_top, lsgpu x11: xdriinfo, xdpyinfo, xprop, xrandr

Installed and firmware-intel-graphics sudo apt install firmware-intel-graphics and put the user in the render group sudo adduser $(whoami) render). This fixed it for me.