Programming Interface Information: The Monitor Records are intended Programming Interfaces that allow the customer to write programs to obtain services of z/VM.

#### MRPRCTOP

Prolog
Control Block Contents
Cross Reference

#### MRPRCTOP Prolog

     DSECT NAME - PRCTOP
     FUNCTION - Map a Monitor record.
     LOCATED BY -
            Through the Monitor Control Area
     REFERENCED CONTROL BLOCKS -
            MRRECHDR    Monitor Record Header
     NAME - MRPRCTOP
     DESCRIPTIVE NAME - Monitor Event Record
                        Domain  5 - Processor Domain
                        Record 14 - System Topology
     DESCRIPTION - Provides System Topology counts and
                   STSI 15.1.x output.
     NOTES -
         1. The system topology monitor records are identical
            and need to stay that way. The identical records
            are MRPRCTOP (D5R14) and MRMTRTOP (D1R26).
         2. For additional information about the format and meaning
            of fields defined in this record (especially the
            PRCTOP_STSI field), refer to the following books:
              - Principles of Operation for the layout of the
                variable length STSI 15.1.x output which is
                documented in Chapter 10 under "STORE SYSTEM
                INFORMATION".  Anyone looking at the STSI data
                in this record should read about the format of
                the data and the CPU Topology Overview contained
                there. (SA22-7832-08)
         3. It is impossible to state every situation in which
            a topology change occurs and this record is cut
            because placement of the LPAR is determined by PR/SM.@U9010PQ
            However, some likely causes include:
            - Activating an LPAR on the CPC
            - Deactivating an LPAR on the CPC
            - VARYing OFF or VARYing ON logical CPUs in LPARs
            - Changes in the available CPC hardware (such as
              taking a node offline for service)

#### MRPRCTOP Control Block Contents

    Offsets
    Dec  Hex  Type        Len  Name (Dim)             Description

       0   0  Structure    36  PRCTOP                 Start of monitor record
       0   0  Character     0  PRCTOP_MRHDR           Record header. See MRRECHDR
                                                      for details.
       0   0  Character    20  MRHDR
       0   0  Unsigned      2  MRHDRLEN
       2   2  Unsigned      2  MRHDRZER
       4   4  Unsigned      1  MRHDRDM
       5   5  Unsigned      1  *
       6   6  Unsigned      2  MRHDRRC
       8   8  Character     8  MRHDRTOD
      16  10  Character     4  *
      20  14  Character     0  MRHDR_END
      20  14  Unsigned      2  PRCTOP_STSIOFF         Offset to STSI 15.1.x
                                                      output
      22  16  Unsigned      2  PRCTOP_STSILEN         Length of STSI 15.1.x
                                                      output in this monitor record
      24  18  Bitstring     1  PRCTOP_PCCMNEST        Maximum MNest value from
                                                      the RSCP Information response
      25  19  Bitstring     1  PRCTOP_RCCMNEST        The selector 2 (x) value
                                                      used by CP on STSI 15.1.x to
                                                      obtain CPU topology
                                                      information.
      26  1A  Unsigned      2  *                      Reserved for IBM Use
      28  1C  Unsigned      4  PRCTOP_RCCTOPPL        Cumulative number of times
                                                      CP checked for system
                                                      topology changes via PTF FC
                                                      2.
      32  20  Unsigned      4  PRCTOP_RCCTOPCH        Cumulative number of times
                                                      CP updated the system
                                                      topology because it changed
                                                      (ie: the PTF FC 2 returned
                                                      CC=1).
      36  24  Character     0  PRCTOP_STSI            STSI 15.1.x output. This
                                                      section is variable length.
                                                      PRCTOP_STSIOFF and
                                                      PRCTOP_STSILEN should always
                                                      be used to determine the byte
                                                      offset of this field in the
                                                      record and the byte length of
                                                      this field.

#### MRPRCTOP Cross Reference

                          Hex           Hex
    Name                  Offset Length Value

    MRHDR                      0     20
    MRHDR_END                 14      0
    MRHDRDM                    4      1
    MRHDRLEN                   0      2
    MRHDRRC                    6      2
    MRHDRTOD                   8      8
    MRHDRZER                   2      2
    PRCTOP                     0     36
    PRCTOP_MRHDR               0      0
    PRCTOP_PCCMNEST           18      1
    PRCTOP_RCCMNEST           19      1
    PRCTOP_RCCTOPCH           20      4
    PRCTOP_RCCTOPPL           1C      4
    PRCTOP_STSI               24      0
    PRCTOP_STSILEN            16      2
    PRCTOP_STSIOFF            14      2

    This information is
    based on z/VM V7R2.0.

    Last updated on 09 August 2020 at 14:50:15.

    Copyright IBM Corporation, 1990, 2020