[26.7.4_1]Intermittent connection drops, kernel thread at 100% CPU seems related

[dragao-azul]

Hi,

Long time lurker (thanks everyone, very useful posts), first time poster.

I'm having an issue since the 15th/16th of September that results in momentary connection drops.

Context:
I use opnsense as a firewall in my homelab, I was away for some time and on my return I immediately started experiencing occasional internet drops for 8-10sec.
OPNsense is virtualised in proxmox with the NICs (I226-V) passthroughed directly to the VM. CPU is in host mode (4 vCPUs, physical CPU is an N150).
On debug, I saw proxmox CPU usage history with higher spikes since the aforementioned dates - so I suspect that's when it started.

Current observations:
If I monitor the ping to 8.8.8.8 or 9.9.9.9 (in fact I used both simultaneously) - I sometimes get spikes of 5-10sec. During this time, I simultaneously looked at CPU usage and the system usage spikes. ChatGPT got involved from here to help debug and may be taking me in wrong directions - it did help spot that clock{clock (0)} consumes 100% of 1 CPU over this time, but I'm not sure if this by itself is very valuable.



I'm trying to progress from here but I feel like I'm getting into the weeds of the kernel's working. Is there a recommended debug strategy for this? Since the dates coincide with the latest updates was any known change introduced? The only thing that stood out (disclaimer disclaimer: helped by ChatGPT to spot it) was "o src: iflib: assorted upstream patches from stable/15" but since it was working before it would imply a regression.

In the meanwhile I'll keep trying to break down this clock thread that spikes.

Many thanks!

[meyergru]

Any specific reason not to leave handling of the physical NIC to PVE via virtio, as described here?

That would also take the igc/iflib driver path inside OPNsense out of the equation.

[dragao-azul]

Thanks meyergru, perhaps not a great one, but when I set things up I followed some friends setup that had used passthrough.
Perhaps silly, but I was also learning my steps and didn't want to accidentally give my proxmox an IP/access via WAN.


Regardless, just to acknowledge the answer and I just ported everything to virtio.
Let me monitor for a while. The first 15min look good, there's very minor peaks, on the healthy side (5% as opposed to 25% of my total CPUs), but sometimes I had 20-30min between peaks so let me give it a few hours.

[dragao-azul]

Not sure if it counts as "solved", but setting up as virtio doesn't cause the issue anymore! The intel drivers might have brought something finicky, but for virtualisation this works! Thanks again!