TL;DR: Some Linux distros and even different kernel versions within a distro have disabled IRQ time accounting. In such case, your monitoring tools will report zero time spent in hardware interrupt handlers (shown as %hi, %irq, hiq, etc). It’s easy to check how your kernel is behaving by looking at /proc/stat and you can still measure interrupt CPU usage using perf and a little creativity. Index Index Problem Explanation Kernel configuration options Measuring IRQ time with perf Different di...
