VMS Help STOP, /CPU, Qualifiers  *Conan The Librarian (sorry for the slow response - running on an old VAX)

1 - /ALL

    Stops all eligible secondary processors in the system's active
    set.

2 - /OVERRIDE_CHECKS

    Directs the STOP/CPU command to bypass a series of checks that
    determine whether the specified processor is eligible for removal
    from the active set.