GSoC community ideas/Speed up Nmap scanning for internet-wide applications

While due to design decisions Nmap has to perform much more tasks than asynchronous port scanners such as masscan or Zmap, we could still improve the scanner's performance to make it work even better while scanning millions of hosts. If I recall correctly, DNS was one of the spots where optimizations could be made. (added by d33tah)

• This is closely related to the Performance/Optimization Specialist idea further down, so see some of the tasks there.
• DNS speedups are always good, but measurement would be the first step. How does Nmap's --min-rate compare to these asynchronous scanners? At what point (in packets-per-second) do they diverge and Nmap cannot keep up?