从net.UDPConn读取锁定PC

Question

As a test I wrote little tool to test the LAN connection between two PCs. It is a client/server model that just sends as many UDP packets as it can and on the other side I read everything I can.
To max out my resources, I start a goroutine for every core my machine has.
Sending, receiving and measuring speed works, but when I get to high throughput (500+ Mb/s), the receiving end becomes completely unresponsive.
If I throttle the connection, I don't have any problems.
Also my CPU maxes out just one core (although i used runtime.GOMAXPROCS(0) and start to receive in runtime.NumCPU goroutines)

I uploaded the code to GitHub over here: https://github.com/femot/lanbench

If I change the client to run locally, the problem does not occur. It only happens, if I start the client from another PC (although the measured speed also tops out at 650 Mb/s)

Answer 1

Your server is limited first by the delta channel with a buffer of 100. I'm sure at any significant packet rate that you will be overwhelming that loop.

This isn't a very good benchmark, since your packet rate is going to be a limiting factor more so than bandwidth. You're specifically only trying to test how fast Go can send and receive 1024byte UDP datagrams.

Regardless of how many goroutines you start, the IO is all going through the network poller in a single thread. If you can't saturate your link with a single core, you're going to need multiple process or you need to do this in another language.