Seeing incorrect offline and online CPUs

[capriciousduck]

Hey

I am running htop in an LXC container that uses the Ubuntu Noble image (Ubuntu 24.04). This time, unlike before, htop shows the "offline" CPUs as well.

This is what I expect:

For example, if I allocate 5 CPUs only to the LXC container, htop should show the 5 vCPUs.

This is what I see:

I see the 5 "online" CPUs and all the other CPUs (of the host) are shown as "offline". Often times, more than 5 CPUs show as online. However, top shows the correct amount of CPUs always.

As you can see from the image below more than 5 CPUs are shown as online

This is the output of top:

Some other info you may find useful

htop version: 3.3.0
os: Ubuntu Noble (Ubuntu 24.04)
host kernel version: 6.8.0-31-generic

[fasterit]

Can you add the PROCESSOR column to see on which CPU your processes are executed?
May be LXC uses more than 5 cores by shuffling load around?

[capriciousduck]

The CPU cores is fixed (i.e will be 5 at all times) but yes the load may run on other cores sometimes but lxcfs will abstract this. In the past, I did not see this issue (on Jammy, Focal, etc,).

Let me know if you need more information.

[capriciousduck]

This happens even in a KVM machine (also has 5 CPUs). I think this is happening only on Ubuntu Noble as I don't see this issue happening on LXC Jammy container which is also running on the same physical host.