centos – High CPU usage by ksoftirqd

We use GCP for running Kubernetes and for communication with our services in different locations using VM masquerading by iptables. The first time we faced an issue with performance when we use only one CPU for masquerading. We fixed it enabling SMP and allowing to use of more than one core, but after it, we faced another issue, after some time ksoftirqd utilize all available cores and VM become unresponsible.

It’s look like this, but for all cores.

Kernel version: Linux gke-masq-sap-v2-group-n1vj 3.10.0-1160.76.1.el7.x86_64 #1 SMP Wed Aug 10 16:21:17 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux

I couldn’t find any related issues in bugtracker. So now we fix issue by restarting this VM.