Subroutine
Subroutine is a priority setting in the VI Execution properties. From the LabVIEW Help:
Select subroutine priority to make the LabVIEW execution system run the VI as efficiently as possible. VIs that you set for Subroutine priority do not share execution time with other VIs. Selecting the subroutine priority also prevents any screen redraws and other system functions from occurring. You cannot abort a VI that has subroutine priority.
When to use the Subroutine Setting
{need to add best practices and rules of thumb for when to use this setting}