viewprof is a text-based interactive GHC .prof viewer.
It has three display modes:
Aggregate cost centers view: This is the default view. It groups cost centers by their name and module name, like the middle section of .prof files.
Call sites view: If you press enter on a cost center, viewprof displays call sites of the cost center you selected. This view tells how much the cost center spent for each call site.
Modules view: If you press M, viewprof displays the module level breakdown. This view tells coarse overview of cost attribution.