I am working on cuda and I have some problem related to thread synchronization. In my code I need threads to execute different part like

one thread -> all thread -> one thread

this is what I want. In the initial part of code only one thread will execute and then some part will be executed by all threads then again single thread. Also the threads are executing in a loop. Can anyone tell me how to do that? It's a kinda urgent. I'll be grateful with any help. Thanks