OPNsense Forum

English Forums => 26.7 Series => Topic started by: dragao-azul on September 21, 2026, 02:10:04 PM

Title: [26.7.4_1]Intermittent connection drops, kernel thread at 100% CPU seems related
Post by: dragao-azul on September 21, 2026, 02:10:04 PM
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!
Title: Re: [26.7.4_1]Intermittent connection drops, kernel thread at 100% CPU seems related
Post by: meyergru on September 21, 2026, 02:30:17 PM
Any specific reason not to leave handling of the physical NIC to PVE via virtio, as described here (https://forum.opnsense.org/index.php?topic=44159.0)?

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