UDP send performance in Node.js

That test is overfly flawed. UDP doesn't guarantee the delivery of anything and doesn't guarantee that it would give any error in case of error.

Your application could send 1000k datagram/s at 1GB/s from the Java application, yet 90% of datagrams never reached the destination... the destination might not even be running.

If you want to do any sort of UDP testing, you need two applications, one on each end. Send numbered datagrams 1, 2, 3... and check what's sent and what's received. Note that UDP doesn't guarantee any ordering of messages.

Kernels manage the localhost network in special ways. There are huge buffers dedicated to it and higher limits, no traffic ever goes through any network cards or drivers. It's very different from sending packets for real.

Tests might seem somewhat okay when they're only done on localhost. Expect everything to fail miserably when it's going through any physical infrastructure for real.

PC1 <-----> switch <-----> PC2

Let's say, there are two computers in the same room linked by a switch. It would be no small feat to achieve 10k/s UDP datagrams on that simple setup, without loosing messages randomly.

And that's just two computers in the same room. It can be a lot worse on the Internet and long distance.

If all you want is to make the performance test go faster, removing the setImmediate call and executing the next send once the first has completed i.e. in the send callback increased its performance to ~100k requests per second on my slowish laptop.

function send(socket, message) {  socket.send(message, SERVER_PORT, (err) => {    send(socket, message);  });}const socket = require('dgram').createSocket('udp4');const message = new Buffer('dsdsddsdsdsjkdshfsdkjfhdskjfhdskjfhdsfkjsdhfdskjfhdskjfhsdfkjdshfkjdshfkjdsfhdskjfhdskjfhdkj');send(socket, message);