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 flexible but will choose speed over flexibility if it is by considerable amount.
12 Answers
Best results you'll get with Shared Memory solution.
Named pipes are only 16% better than TCP sockets.
Results are get with IPC benchmarking:
- System: Linux (Linux ubuntu 4.4.0 x86_64 i7-6700K 4.00GHz)
- Message: 128 bytes
- Messages count: 1000000
Pipe benchmark:
Message size: 128
Message count: 1000000
Total duration: 27367.454 ms
Average duration: 27.319 us
Minimum duration: 5.888 us
Maximum duration: 15763.712 us
Standard deviation: 26.664 us
Message rate: 36539 msg/s
FIFOs (named pipes) benchmark:
Message size: 128
Message count: 1000000
Total duration: 38100.093 ms
Average duration: 38.025 us
Minimum duration: 6.656 us
Maximum duration: 27415.040 us
Standard deviation: 91.614 us
Message rate: 26246 msg/s
Message Queue benchmark:
Message size: 128
Message count: 1000000
Total duration: 14723.159 ms
Average duration: 14.675 us
Minimum duration: 3.840 us
Maximum duration: 17437.184 us
Standard deviation: 53.615 us
Message rate: 67920 msg/s
Shared Memory benchmark:
Message size: 128
Message count: 1000000
Total duration: 261.650 ms
Average duration: 0.238 us
Minimum duration: 0.000 us
Maximum duration: 10092.032 us
Standard deviation: 22.095 us
Message rate: 3821893 msg/s
TCP sockets benchmark:
Message size: 128
Message count: 1000000
Total duration: 44477.257 ms
Average duration: 44.391 us
Minimum duration: 11.520 us
Maximum duration: 15863.296 us
Standard deviation: 44.905 us
Message rate: 22483 msg/s
Unix domain sockets benchmark:
Message size: 128
Message count: 1000000
Total duration: 24579.846 ms
Average duration: 24.531 us
Minimum duration: 2.560 us
Maximum duration: 15932.928 us
Standard deviation: 37.854 us
Message rate: 40683 msg/s
ZeroMQ benchmark:
Message size: 128
Message count: 1000000
Total duration: 64872.327 ms
Average duration: 64.808 us
Minimum duration: 23.552 us
Maximum duration: 16443.392 us
Standard deviation: 133.483 us
Message rate: 15414 msg/s
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.
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.
If you do not need speed, sockets are the easiest way to go!
If what you are looking at is speed, the fastest solution is shared Memory, not named pipes.
Named pipes and sockets are not functionally equivalent; sockets provide more features (they are bidirectional, for a start).
We cannot tell you which will perform better, but I strongly suspect it doesn't matter.
Unix domain sockets will do pretty much what tcp sockets will, but only on the local machine and with (perhaps a bit) lower overhead.
If a Unix socket isn't fast enough and you're transferring a lot of data, consider using shared memory between your client and server (which is a LOT more complicated to set up).
Unix and NT both have "Named pipes" but they are totally different in feature set.
I know this is a super old thread but it's an important one so I'd like to add my $0.02. UDS are much faster in concept for local IPC. Not only are they faster but if your memory controller supports DMA then UDS causes almost no load on your CPU. The DMA controller will just offload memory operations for the CPU. TCP needs to be packetized into chunks of size MTU and if you don't have a smart nic or TCP offload somewhere in specialized hardware that causes quite a bit of load on the CPU. In my experiences UDS are around 5x faster on modern systems in both latency and throughput.
These benchmarks come from this simple benchmark code. Try for yourself. It also supports UDS, pipes, and TCP: https://github.com/rigtorp/ipc-bench
I see a CPU core struggling to keep up with TCP mode while sitting at about ~15% load under UDS thanks to DMA. Note that Remote DMA or RDMA gains the same advantages in a network.
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