Linux kernel API change
- Write one buffer into multiple FD, to do multicast at IP level without register and fixed group (because can change all the time)
- Pass the event AND datas pointer + size into the program via epollWait to prevent buffer copy (less memory bandwith) and less round trip time.
- Fast path for write, need get the write buffer current pointer, and max size (less memory bandwith). This is possible only in cooperative mode.