I recently discovered that `perf` itself can spit out flamegraphs. My workflow has been:

    $ perf record -g -F 99 ./my-program
    $ perf script report flamegraph

You can also run `perf script -F +pid > out.perf` and then open `out.perf` in Firefox's built-in profile viewer (which is super neat) https://profiler.firefox.com