> Are we really discussing saving a share of a µS of CPU time for every HTTP

Yes because not everyone is satisfied with [this abomination](http://www.techempower.com/benchmarks/#section=data-r8&hw=i7&test=json) and because these are the sorts of things you have to consider if you want to outperform node.js using userland PHP code (which I am doing quite successfully). I know other people aren't working on this scale but I am. It's a real consideration. Efficiency should not be discarded lightly.