I have a utility routine which I have optimized as much as I can.
    I need to know who is calling it and how often, so I can reduce
    the number of calls to it. How do I get this information?

    Use /MAIN_IMAGE=utility-routine on the plot command. This gives
    you the following options:

    -  PLOT CALL_TREE BY CHAIN_ROUTINE will list all the call chains
       which pass through utility-routine with the number of data
       points for each call chain.

    -  PLOT/STACK=1 PROGRAM BY ROUTINE will list all the callers of
       utility-routine.

    -  If one particular caller of utility-routine is of interest,
       try the following:

  PCAA> SET FILTER filter-name CHAIN=(*,caller,utility-routine,*)

    This will assure that the data being viewed is only of those
    whose chains have a subchain caller,utility-routine.

    -  Many other combinations of /CUMULATIVE, /MAIN_IMAGE, /STACK
       with various filters and nodespecs may be useful.