The article explains how Linux soft interrupts work, why they can become a CPU bottleneck under heavy network traffic, and provides detailed analysis, code examples, monitoring tools, and optimization strategies to diagnose and mitigate the issue.
The article examines why applications experience slower performance after being containerized on Kubernetes, presenting benchmark comparisons, analyzing increased soft‑interrupt overhead due to the Calico ipip overlay, and proposing network optimizations such as ipvlan modes and Cilium to restore efficiency.
This article provides a comprehensive analysis of the Linux kernel's handling of localhost network I/O, detailing how packets destined for 127.0.0.1 bypass physical network interfaces, traverse the routing table, and utilize the loopback virtual device and soft interrupts for efficient intra-machine communication.
During performance testing, the article explains how high soft‑interrupt CPU usage can be diagnosed via /proc/interrupts, and demonstrates binding network‑card interrupt queues to individual CPU cores using commands and scripts, resulting in balanced CPU load and reduced interrupt overhead.
