iperf is a tool for measuring maximum TCP and UDP bandwidth performance. It allows the tuning of various parameters and TCP/UDP characteristics and reports bandwidth, delay jitter, and datagram loss.
iperf3 is a new implementation from scratch, with the goal of a smaller, simpler code base, and a library version of the functionality that can be used in other programs.
iperf3 also has a number of features found in other tools such as nuttcp and netperf, but were missing from iperf2.X.
Some new features in iperf3 include:
- reports the number of TCP packets that were retransmitted
- reports the average CPU utilization of the client and server (-V flag)
- support for zero copy TCP (-Z flag)
- JSON output format (-J flag)
The current version of iperf3 (released 10 January 2014) is 3.0.1.