If you run one of the processes or threads in a group and it hits a barrier point, you see an H next to the process or thread name in the Root Window and the word [Held] in the title bar in the main Process Window. Barrier points are always shared.

If you create a barrier and all the process’s threads are already at that location, TotalView won’t hold any of them. However, if you create a barrier and all of the processes and threads are not at that location, TotalView holds any thread that is already there.