When selected (which is the default), TotalView displays manager processes and threads.

Manager processes are processes such as mpirun that are used to launch and perhaps control an HPC job. While they are important to the program, they are not what you’ll be debugging (unless, of course, you’re creating your own starter process).

Manager threads are threads created by the operating system that support your program’s activities.

In most cases, you are not interested in these processes and threads, so clearing this command is usually what you want to do.