[bunderbunder]

I'm not even sure it's bonkers if you have a lot of traffic. It depends on the nature of the traffic and how you define "a lot". In general, though, it's amazing how low latency a function call that can handle passing data back and forth within a memory page or a few cache lines is compared to inter-process communication, let alone network I/O.

The corollary to that is, it's amazing how far you can push vertical scaling if you're mindful of how you use memory. I've seen people scale single-process, single-threaded systems multiple orders of magnitude past the point where many people would say scale-out is an absolute necessity, just by being mindful of things like locality of reference and avoiding unnecessary copying.