Today I have added Crow to my own WebFrameworkBenchmark and my results are quite different than yours. Crow is far below Netty and some C frameworks, it is close to Go performance.
Can you give me some information if maybe I am doing something wrong so I don't get performance comparable to Netty. Note I used latest master compiled with GCC 4.8, and and boost 1.54.0. Other C frameworks use exactly same compiler, but get much better results.