lost_percent greater than 100%

[joudinet]

Context

• Version of iperf3: 3.12

• Hardware: armv7l

• Operating system (and distribution, if any): Linux (Buildroot)

• Other relevant information (for example, non-default compilers,
  libraries, cross-compiling, etc.):
  Optional features available: CPU affinity setting, IPv6 flow label, TCP congestion algorithm setting, sendfile / zerocopy, socket pacing, authentication, bind to device, support IPv4 don't fragment

Bug Report

Running an UDP test with a bitrate of 300Mb/s, Iperf3 sometimes reports a value of lost_percent greater than 100.

• Expected Behavior

I expect lost_percent to always be below 100.

• Actual Behavior

"lost_percent": 179.64904660556834,

• Steps to Reproduce

iperf3 --json --client TARGET_IP --udp --bitrate 300M --omit 5 --time 5 --interval 0

where the link to TARGET_IP reports a TCP throughput below 300 Mb/s.

• Possible Solution

No idea. I guess either the counting of sent packets or the counting of lost packets is wrong.