The section just above the part you have linked also explains that tokio lets you pick the runtime scheduler - https://docs.rs/tokio/latest/tokio/runtime/index.

The section just above the part you have linked also explains that tokio lets you pick the runtime scheduler - https://docs.rs/tokio/latest/tokio/runtime/index.html#runtime-configurations https://docs.rs/tokio/latest/tokio/runtime/index.html#runtim... - so you can run on single or multiple threads (the default is the latter with core and blocking threads as mentioned in the section you linked). I think you can mix them (or you can, as mentioned in the link, have a separate runtime for CPU-bound tasks) but it is probably easier to use Rayon.