Can anyone point me to the tool they use to generate the concurrency graphs, such as this one https://user-images.githubusercontent.com/410484/93755338-ba...? Is it something OCaml specific?
It uses the event logging infrastructure in multicore which outputs json.
Normal OCaml has integrated this since 4.11: https://ocaml.org/releases/4.11/htmlman/instrumented-runtime... but switches to the Common Tracing Format (CTF) so you'll need an extra step to convert it to a format Chrome tracing can ingest.