When synclock is active, other threads will be stored into a 'waiting queue' or whatever you want to call it. Just doing nothing. When End Synclock is used the first thread in the queue will be be punched in the face to wake him up and he will continue where he left of.

So the threads that are waiting aren't asking the other thread that holds the lock. Are you done yet, are you done yet, constantly. They just say, hey I'll wait here in this queue. Give me a signal when your done .