OpenVPN Support Forum

Hi,
Using openvpn on an aws instance using Amazon Linux 2. When a client connects and tries to transfer a file (from a file on another server), it goes quite slow and on the instance the cpu usage is almost entirely used (99%) by ksoftirqd/1 for the duration of the transfer.

Is there any pointers to troubleshoot this, I can find very little in relation to ksoftirqd/1 in relation to openvpn, has anyone else seen this?

A quick search for ksoftirqd using duckduckgo gives plenty of results about CPU usage.

High CPU usage by ksoftirqd/1 during OpenVPN file transfers on your Amazon Linux 2 instance can be addressed by optimizing OpenVPN configuration (e.g., cipher selection, multithreading), checking network interface settings (MTU, offloading), and monitoring for network congestion. Consider increasing CPU resources if necessary and use tools like perf for in-depth analysis.