I thought I'd take a look at the epoll_reactor implementation. I thinking of using asio proactor style code to use kernel bypass libraries. I wanted to see how you do async IO with a pool of threads. I think I see a bug. None of the operations there done outside of the lock seem thread safe. They unsafely modify linked lists. lock.unlock(); read_op_queue_.complete_operations(); write_op_queue_.complete_operations(); except_op_queue_.complete_operations(); Chris