Comment by AaronFriel

I think it's a false dichotomy. Delayed ACK and Nagle's algorithm each improve the network in different ways, but Nagle's specifically allows applications to be written without knowledge of the underlying network socket's characteristics.

But there's another way, a third path not taken: Nagle's algorithm plus a syscall (such as fsync()) to immediately clear the buffer.

I believe virtually all web applications - and RPC frameworks - would benefit from this over setting TCP_NODELAY.

It would also be more elegant than TCP_CORK, which has a tremendous pitfall: failing to uncork can result in never sending the last packet. And it's easy to implement by adding a syscall at the end of each request and response. Applications almost always know when they're done writing to a stream.