once i run a .py to send 10000 UDP(lengh is: 110)  using socket sendto(), a server receive about 400 msgs quickly, and later became very slow for more than 10s each msg.
it is weird if i run the .py again, another 400 msgs received quickly.
is there a limit of buffer or UDP problem, for this situation?
yes i got it! UDP is uncertain to destination, continues package jams after 300 msgs. so i have to add time.sleep(0.2) to make it work. Now i'm trying multiple server process for time interval.
It might just be that other things are using your network card to send at the same time, and the system can only send 400ish from your application at a time before something else needs to use the NIC. It sounds more like an issue of network usage, than a problem with UDP or something.
UDP sendto() became very low, python