The problem with looping on the input from named pipes is that after the first read you're left with an EOF for the second read¹, so the loop exits. Subsequently you can't loop on a named pipe without working some serious voodoo (over-riding CORE::GLOBAL::eof()?). So this provides with many excuses to do dubious things such as using goto(), labels and (dum dum dum) infinite loops. Personally I'd go with an infinite loop opening the FIFO on each iteration, or take have a good long think about it. Good luck!
HTH

broquaint

¹unless you have something writing faster than perl can read