An actor-model multi-core scheduler for OCaml 5.
Riot is an actor-model multi-core scheduler for OCaml 5. It brings Erlang-style concurrency to the language, where lighweight process communicate via message passing.
open Riot
type Message.t += Hello_world
let () =
Riot.run @@ fun () ->
let pid =
spawn (fun () ->
match receive () with
| Hello_world ->
Logger.info (fun f -> f "hello world from %a!" Pid.pp (self ())))
in
send pid Hello_worldAt its core Riot aims to offer:
-
Automatic multi-core scheduling – when you spawn a new Riot process, it will automatically get allocated on a random scheduler.
-
Lightweight processes – spawn 10 or 10,000 processes as you see fit.
-
Fast, type-safe message passing
-
Selective receive expressions – when receiving messages, you can skim through a process mailbox to consume them in arbitrary order.
-
Process links and monitors to keep track of the lifecycle of processes
Riot also includes:
-
Supervisors to build process hierarchies
-
Logging designed to be multicore friendly
At the same time, there's a few things that Riot is not, and does not aim to be.
Primrarily, Riot is not a full port of the Erlang VM and it won't support several of its use-cases, like:
- supporting Erlang or Elixir bytecode
- hot-code reloading in live applications
- function-call level tracing in live applications
- ad-hoc distribution
git clone https://github.com/leostera/riot
cd riot
opam install .
After that, you can use any of the examples as a base for your app, and run them:
dune exec ./my_app.exe
Riot is the continuation of the work I started with Caramel, an Erlang-backend for the OCaml compiler.
It was heavily inspired by eio by the OCaml Multicore team and
miou by Calascibetta Romain and the
Robur team, as I learned more about Algebraic Effects. In particular the Proc_state is based on the State module in Miou.
And a thousand thanks to Calascibetta Romain and Antonio Monteiro for the discussions and feedback.