> Local TCP sockets can also bypass the kernel if you have a user-space TCP stack. I don't know if you can do this with unix domain sockets (I've never tried).

> Local TCP sockets can also bypass the kernel if you have a user-space TCP stack. I don't know if you can do this with unix domain sockets (I've never tried). Kernel bypass exists because hardware can handle more packets than the kernel can read or write, and all the tricks employed are clever workarounds (read: kinda hacks) to get the packets managed in user space. This is kind of an orthogonal problem to IPC, and there's already a well defined interface for multiple processes to communicate without buffering through the kernel - and that's shared memory. You could employ some of the tricks (like LD_PRELOAD to hijack socket/accept/bind/send/recv) and implement it in terms of shared memory, but at that point why not just use it directly? If speed is your concern, shared memory is always the fastest IPC. The tradeoff is that you now have to manage the messaging across that channel.