Check out the techempower framework benchmarks. Netty can do over a million http responses per second on a reasonable machine.

On Linux it uses an epoll native driver and is asynchronous. The framework makes it possible to write proxies in a few lines.

If you want to beat netty by a significant margin you'll probably need to use kernel bypass

C++ 17 Networking TS is based on ASIO. It will be very interesting if netty performs better than ASIO based code for the same task.

They both use epoll underneath. Netty will likely perform better because it has a robust thread pool implementation.

Would suggest to look at how thread pooling works in ASIO before making conclusions.

ASIO does all that. And it compiles to machine code. What you're basically trying to argue is a well-written C++ application will be slower than a well-written java application. That's not going to happen -- at best they will be the same performance.

Netty certainly has a more impressive list of projects using it in real-world high-volume scenarios. That's probably what wins in this case...enough high volume end users such that you've gotten enough edge cases to tweak the software and iron out bugs.

If I had to pick something in the C/C++ space to implement a custom proxy, I would probably stick to something where I could find a similar list of established high volume real world users. Facebook's Proxygen, or some customized HAProxy maybe.

I was trying to say in a nice way that it's unlikely you've created something as fast as netty because a lot of people spent a lot of time optimizing it.

Netty is also a lot easier to extend and more portable