1    /STACK_PCS

    Specifies that stack PC values for counter data are to be
    collected. If you use /STACK_PCS, further SET VCOUNTERS requests
    assume a default of /STACK_PCS.

2    /NOSTACK_PCS

    Specifies that no stack PC values for counter data are to be
    collected. This is the default setting upon entry into the
    Collector.