I had the same experience/question at some point when I noticed (and investigated), why didn't a new Ubuntu Linux install break out interrupt usage in vmstat an

I had the same experience/question at some point when I noticed (and investigated), why didn't a new Ubuntu Linux install break out interrupt usage in vmstat anymore. [1] Perf+flamegraphs were able to catch in-interrupt-handling samples as I was on a bare metal machine with PMU counters accessible. But the various NVMe I/O completion interrupts happened all over the place, even when the CPUs were in random userspace code sections. Neither the bottom-up & top-down FlameGraph approach made it visually clear in this case. But since interrupt time did show up and since the FlameGraph JS tool had a text search box, I searched for "interrupt" or "irq" in the search box - and the JS code highlighted all matching sections with purple color (completely distinct from the classic color range of flamegraphs). And seeing that purple color all over the place made me smile and gave me a strong visual "a-ha" moment. Probably with some extra JS tinkering, these kinds of "events scattered all over the place" scenarios could be made even clearer. [1] https://news.ycombinator.com/item?id=26139611 https://news.ycombinator.com/item?id=26139611 (2021)