The CANCEL COUNTERS Collector command cancels execution counters
    at the program locations specified by the node specification
    or by the /ALL qualifier. Any node specifications you cancel
    must have been established by previous SET COUNTERS commands.
    If you first set an execution counter at a program location
    with SET COUNTERS and then cancel it with CANCEL COUNTERS, no
    execution count is measured at that location when the GO command
    is entered.