A meta comment, not really related to your point, but I found it amusing in context. You're writing about how doing lots of little things in an HTTP server is

A meta comment, not really related to your point, but I found it amusing in context. You're writing about how doing lots of little things in an HTTP server is inefficient; and you're replying to John Nagle, who contributed the Nagle TCP optimization that debounces tiny sends with a little bit of delay, in the hope of doing more work in one go! (On topic of your HTTP example: this is where generational GC can shine. Ideally one of your younger generations covers the full allocation cycle for a request & response, so that nothing survives the collection and it's ultra-cheap to collect since tracing the roots doesn't find anything. The nice thing about GC instead of an explicit arena is that it's global, so you don't need to contort all your library calls to ensure they're using the right allocator.)