[MrBuddyCasino]

Ok, I was aware of the difference between Direct vs. Heap ByteBuffers, and I guess I understand the argument about poll/epoll. Now what I don't quite get is why most open source projects chose to use the slower implementation. Don't they know any better? Is it a portability issue? Bugs in certain JVM/OS combinations? Netty.io claims to be 0-copy capable, so I guess that this must be one of the good ones that are available?

[xxs]

After seeing the message I've decided to check netty.io's code and I am pleasantly surprised. It has been ages since I checked the project. They use almost all tricks in the book - CAS around selector.wake(), handling the zero returned keys,ref. counting buffers allocator, even a SC/MP queue.

Only couple of downsides: 1) there appears to be the lack of bounded queues and it's a non-trivial one. Bounded queues are important to ensure proper back-pressure on 'producers' and/or killing slow peers. 2) encoding pipeline may require serializing the same message multiple times when sending to multiple clients even if the serialization results into the same byte stream. However this is really a minor issue.

Like I've said I'm pleasantly surprised.