I strongly recommend not using this. Instead use pprof - it has a MUCH better interactive flamegraph, plus other nice performance visualisations (e.g. a call graph):

https://github.com/google/pprof

    go install github.com/google/pprof@latest
    pprof -http=: prof.out

I normally collect the profiles with gperftools (https://github.com/gperftools/gperftools) and then just

    LD_PRELOAD=/usr/lib/libtcmalloc_and_profiler.so CPUPROFILE=prof.out <your command>

I've been meaning to try Samply though. Not sure if it works with pprof.

OP here. In this particular case, I used https://github.com/flamegraph-rs/flamegraph