VMS Help Sys Parameters, PANUMPOLL  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    PANUMPOLL establishes the number of CI and DSSI ports to be
    polled each polling interval. The normal setting for PANUMPOLL
    is 16.

    On systems with less powerful CPUs, the parameter may be useful
    in applications sensitive to the amount of contiguous time that
    the system spends at IPL 8. Reducing PANUMPOLL reduces the amount
    of time spent at IPL 8 during each polling interval, while
    increasing the number of polling intervals needed to discover
    new or failed ports.

    If CI or DSSI devices are not configured on your system, this
    parameter is ignored.

    PANUMPOLL is a DYNAMIC parameter.