Processes and threads at a barrier point are held or stopped, as follows:
Held
A held process or thread cannot execute until all the processes or threads in its group are at the barrier, or until you manually release it. The various go and step commands from the Group, Process, and Thread menus cannot start held processes.
Stopped
When all processes in the group reach a barrier point, TotalView automatically releases them. They remain stopped at the barrier point until you tell them to resume executing.
You can manually release held processes and threads with the Hold and Release commands found in the Group, Process, and Thread menus. When you manually release a process, the go and step commands become available again.