You may not even need to go that deep.

Just strace (follow forks) and look what commands get exec'd.

"Why does musl make my Rust code so slow?" But he's measuring mostly the compiler performance in "cargo build". Is he writing the same amount of data to disk in the same experiments? Seems like there's a lot of opportunity for some shallow investigation to find out more.

If he's benchmarking on docker, I'm not sure that perf works in docker.

Then benchmark outside docker?

Depends on the kernel.perf_event_paranoid sysctl.