The graph in your terminal shows 2.3% CPU overhead. You spent $35 on a Raspberry Pi 5, configured Docker Compose to run your workload, and fired up Linux Perf. The numbers look clean. The coffee is cold.
But you're profiling inside a container. And containers lie.
I found this pattern buried in a Japanese developer's write-up on Qiita — the kind of practical, get-it-done resource that rarely crosses into English-language discourse. The author (oichan00) documented their setup for running Linux Perf inside Docker Compose on a Raspberry Pi 5. It's the kind of thing that makes you nod along: "Yeah, that makes sense. Perf for containerized workloads, cheap hardware, portable setup."
It does make sense. Until it doesn't.
The Skeleton Measurement Pattern
