This repo has the exact same functionality as fq-detection-simple but is faster since it's written in C while fq-detection-simple is written in Python. It's about twice as fast. It can detect fair queuing confidently on links with a capacity of up to around 3 Gbit/s.
Compile using gcc or clang like this:
gcc server.c -Ofast -o server && gcc client.c -Ofast -o client
Then run as described in the readme of fq-detection-simple.