IPC performance: Named Pipe vs Socket

Question

Everyone seems to say named pipes are faster than sockets IPC. How much faster are they? I would prefer to use sockets because they can do two-way communication and are very

Answer 1

I would suggest you take the easy path first, carefully isolating the IPC mechanism so that you can change from socket to pipe, but I would definitely go with socket first. You should be sure IPC performance is a problem before preemptively optimizing.

And if you get in trouble because of IPC speed, I think you should consider switching to shared memory rather than going to pipe.

If you want to do some transfer speed testing, you should try socat, which is a very versatile program that allows you to create almost any kind of tunnel.

Answer 2

For two way communication with named pipes:

• If you have few processes, you can open two pipes for two directions (processA2ProcessB and processB2ProcessA)
• If you have many processes, you can open in and out pipes for every process (processAin, processAout, processBin, processBout, processCin, processCout etc)
• Or you can go hybrid as always :)

Named pipes are quite easy to implement.

E.g. I implemented a project in C with named pipes, thanks to standart file input-output based communication (fopen, fprintf, fscanf ...) it was so easy and clean (if that is also a consideration).

I even coded them with java (I was serializing and sending objects over them!)

Named pipes has one disadvantage:

• they do not scale on multiple computers like sockets since they rely on filesystem (assuming shared filesystem is not an option)

Answer 3

You can use lightweight solution like ZeroMQ [ zmq/0mq ]. It is very easy to use and dramatically faster then sockets.

Answer 4

I'm going to agree with shodanex, it looks like you're prematurely trying to optimize something that isn't yet problematic. Unless you know sockets are going to be a bottleneck, I'd just use them.

A lot of people who swear by named pipes find a little savings (depending on how well everything else is written), but end up with code that spends more time blocking for an IPC reply than it does doing useful work. Sure, non-blocking schemes help this, but those can be tricky. Spending years bringing old code into the modern age, I can say, the speedup is almost nil in the majority of cases I've seen.

If you really think that sockets are going to slow you down, then go out of the gate using shared memory with careful attention to how you use locks. Again, in all actuality, you might find a small speedup, but notice that you're wasting a portion of it waiting on mutual exclusion locks. I'm not going to advocate a trip to futex hell (well, not quite hell anymore in 2015, depending upon your experience).

Pound for pound, sockets are (almost) always the best way to go for user space IPC under a monolithic kernel .. and (usually) the easiest to debug and maintain.