I remember seeing a graph where http/af, a http server, was close to Go net/http. I'll try to run https://github.com/ocaml-multicore/retro-httpaf-bench and report back. I also found another graph, but I'm too colorblind to read it properly https://user-images.githubusercontent.com/554131/131155247-f....

Edit: the benchmark fails to build

We don't compare against Go pervasively. Benchmarking across languages is hard generally, but here is a result on a specific benchmark comparing several versions of OCaml benchmarks against Go and Rust on a Http server benchmark: https://github.com/ocaml-multicore/retro-httpaf-bench/pull/1....

If there are suggestions to make the Go and Rust versions, please feel free to tell us how in the issue tracker.

Our paper from ICFP last year has extensive benchmarks against stock OCaml: https://arxiv.org/abs/2004.11663

In short there should be very little performance difference against stock.

As KC has linked in a sibling comment there's a project going to explore using effects to write high performance IO libraries and that has some early benchmarks.

Yes, check out https://watch.ocaml.org/videos/watch/playlist/7a4ad26a-b8c5-... for some interesting comparisons.