[BUG] btop shows absolute zero CPU temp

[joske]

On an amazon EC2 instance (not sure, but a VM for sure), a colleague of mine saw the CPU temp as -273 C:

To Reproduce

not known if it is like this on all VMs

Expected behavior

a reasonable CPU temp

Info (please complete the following information):

• btop++ version: btop -v 1.2.13
• Binary: snap install btop
• (If compiled) Compiler and version:
• Architecture: [x86_64, aarch64, etc.] uname -m x86_64
• Platform: Linux
• (Linux) Kernel: uname -r 5.15.0-1022-aws
• (OSX/FreeBSD) Os release version: ubuntu 20.04.5
• Terminal used: not known - probably not relevant
• Font used: not known - not relevant

[joske]

Ok, in the guest OS, there's nothing in /sys/class/hwmon. Also no coretemp in /sys/devices/platform so I guess there's nothing more to do than not show the temp if it's 0.

[aristocratos]

@joske
It also looks in /sys/class/thermal.
Regardless, don't think I've ever seen the sensors data being passed down from the VM host to the guest. So unless there is specific functionality built in to do this, I wouldn't trust any sensors data inside a VM.

He could always just set show_temp config option to false, I mean, that's why it's there.

Although acknowledging that sub-zero cooling is extremly rare; ignoring the temp below zero would be throwing away valid data if the temp is below 0.

[aristocratos]

But who knows, maybe amazon has built quantum servers and managed to cool the system to 273.4 that gets rounded down to 273 :)

[joske]

I'll ask him again tomorrow, I also received an EC2 instance, also installed btop via snap, and in that machine, btop just doesn't show the temperature.

[aristocratos]

and in that machine, btop just doesn't show the temperature.

That would be the expected in a VM, not sure why he as sensors picking anything up at all.

[FlamenWolf]

I'm on PopOS with no VM and I have the same bug. I have a tool named Vitals I got off of gnome extensions and it detects my cpu temperature with no problem.

[azzydoesgit]

I'm on PopOS with no VM and I have the same bug. I have a tool named Vitals I got off of gnome extensions and it detects my cpu temperature with no problem.

What hardware are you using? I'm on PopOS as well and have never had any issues.

[vitaly-zdanevich]

It showing 1 degree for me, my first thought was that wow my big watercooling works so great.

Previously on the same machine I had some normal temperature, in BIOS I see real ~38 degrees.

Ubuntu 22.02.2 LTS.