UNIX套接字与共享内存消息更快

Question

I am looking at a linux server program which, for each client, creates some shared memory and uses message queues (a C++ class called from the code) in that shared memory to send messages to and fro. On the face of it this sounds like the same usage pattern as domain sockets - ie have a server program that sends and recvs payloads from its clients.

My question is - what extra work do unix domain sockets do? What could conceivably cause shared memory with a message queue to be faster than a socket and vice versa?

My guess is there is some overhead to calling send and recv, but I'm not exactly sure what. I might try and benchmark this, just looking for some insight before I do this.

Answer 1

Here is one discussion: UNIX Domain sockets vs Shared Memory (Mapped File)

I can add that sockets are very primitive, just a stream of bytes for stream sockets. This may actually be an advantage - it tends to make messages between different subsystems small and simple, promoting lean interfaces and loose coupling. But sometimes, shared memory is really useful. I used shared memory in a C++ Linux back-end to a data-intensive Google Maps application - the database was just huge (+1 Gigabyte) png rasters in shared memory.