drop

Documentation

Overview

drop is a UDP packet sink: it receives every packet sent to a UDP port and throws it away. Because it does almost no work per packet, it's a handy way to measure how fast this library (and your NIC) can pull packets into userspace — i.e. raw receive packets-per-second.

go build -o drop ./examples/drop
sudo ./drop -iface eth0 -port 9999

Then blast it from another machine, e.g. with a UDP flood generator:

# small packets stress pps; large packets stress bandwidth
sudo pktgen / udpblast / iperf3 -u -c <host> -p 9999 -b 0 -l 64

It prints receive pps and bit/s once a second, plus drop counters split into nic-side (the NIC ran out of rx descriptors) and app-side (this program didn't drain its rx ring fast enough, broken out per queue) so you can see whether you're losing packets and which stage is the bottleneck.