$ git clone https://github.com/brendangregg/FlameGraph
$ cd FlameGraph
$ sudo perf record --call-graph=dwarf <cmd>
$ sudo perf script | ./stackcollapse-perf.pl > out.perf-folded
$ ./flamegraph.pl out.perf-folded > perf.svg

$ git clone https://github.com/brendangregg/FlameGraph
$ cd FlameGraph
$ sudo offcputime-bpfcc -df -p `pgrep -nx mytest` 3 > out.stacks
$ ./flamegraph.pl --color=io --title="Off-CPU Time Flame Graph" --countname=us < out.stacks > out.svg