alt Hacker News> In the steady state, a webserver would have almost no garbage collector activity
I recently wrote my own zero allocation HTTP server and while the above statement is possible to achieve, at some point you need to make a decision on how you handle pipelined requests that aren't resolved synchronously. Depending on your appetite for memory consumption per connection, this often leads to allocations in the general case, though custom memory pools can alleviate some of the burden.
I didn't see anything in the article about that case specifically, which would of been interesting to hear given it's one of the challenges I've faced.
Good point; I've decided to simply not support HTTP/1.1 pipelines, and to have a connection pooling layer for HTTP/2 instead that takes care of this.
In OxCaml, it has support for the effect system that we added in OCaml 5.0 onwards, which allows for a fiber to suspend itself and be restarted via a one-shot continuation. So it's possible to have a pipelined connection stash away a continuation for a response calculation and be woken up later on when it's ready.
All continuations have to be either discarded explicitly or resumed exactly once; this can lead to memory leaks in OCaml 5, but OxCaml has an emerging lifetime system that guarantees this is safe: https://oxcaml.org/documentation/parallelism/01-intro/ or https://gavinleroy.com/oxcaml-tutorial-icfp25/ for a taste of that. Beware though; it's cutting edge stuff and the interfaces are still emerging, but it's great fun if you don't mind some pretty hardcore ML typing ;-) When it all settles down it should be very ergonomic to use, but right now you do get some interesting type errors.