How to configure iperf-3.1.3-win64 to generate 99.5% throughput traffic on 1Gbps Ethernet?

[lksark]

I would like to ask how can we configure iperf-3.1.3-win64 to generate 99.5% or 995 Mbits/sec throughput traffic? We managed to get ~943 Mbits/sec traffic on 1Gbps Ethernet.

Our computers are running on Microsoft Windows 10 Pro with 16GB RAM.

[davidBar-On]

Hi, 0.94Gbps on a 1Gbps interface seems quite good. Also, the bottleneck may be in the network cards, network buffers, etc, and not in iperf3.

Regarding iperf3, using UDP (-u) may allow increasing the throughput, but for that to work you need to limit the sent throughput to 1Gbps (-b G) or a little bit more and try different packet sizes. Note that TCP default packet is 128KB and UDP default is 1460 bytes, so try different sizes between these values (using the -l` option). For UDP, the throughput is measured on the receiver since packets may be lost.

You can also try setting different TCP packets sizes - greater or smaller than the default 128KB.

Another thing that may help is running few streams in parallel (-P option) - TCP or UDP. In this case, the cumulative streams throughput may be higher then a single stream. Note that when using multi-streams the throughput set by -b is for each stream, so e.g. for UDP test using 4 streams (P 4) set throughput to 250KB (-b 250KB).

One more option that can help is the burst count. You may try setting it to 20 or 30 (default is 10). This is done using the -b option: to set burst count to 20 use for TCP use -b /20 and for UDP -b 1G/20.

Note that iperf3.1.3 is very old, and probably not all the options are supported. It is better to upgrade to a new version (can be downloaded from here - not an official site). Also, iperf3.16 is multi-threaded which may help with the parallel streams (-P) tests.