The Collector provides two data kinds for sampling vector-
    processing information: vector PC sampling and vector CPU
    sampling. You use the SET command, as shown in the following
    example, to enable sampling of PC values for random vector
    instructions:

  PCAC> SET VPC_SAMPLING

    The preceeding command enables the sampling of vector PC values
    and shows you where the wall-clock time is being spent in the
    application performing vector instructions. The sampling rate
    defaults to an interval of 10 milliseconds and includes all
    the idle process time associated with running the program. Call
    stack information is collected by default. The following command
    enables the sampling of vector PC values and lets you examine the
    particular areas of your application where process time is spent
    performing vector instructions.

  PCAC> SET VCPU_SAMPLING

    The sampling rate defaults to an interval of 10 milliseconds
    and includes only the time that the application is running on
    the processor (process clock time). Call stack information is
    collected by default.

    When you sample the vector PC values, you can determine the
    scalar/vector parallelism throughout your entire program. The
    collection of vector PC or CPU sampling data provides you with
    the following information:

    o  The program counter of the vector instruction

    o  The program relative timestamp

    o  The vector instruction opcode

    o  The vector stride

    o  The vector control word (instruction dependent)

    o  The vector length register

    o  The vector mask register

    o  Call stack information (optionally)