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

MRIODDEV

Prolog
Control Block Contents
Cross Reference

MRIODDEV Prolog

 DSECT NAME - IODDEV
 FUNCTION - Map a Monitor record.
 LOCATED BY -
        Through the Monitor Control Area
 REFERENCED CONTROL BLOCKS -
        MRRECHDR    Monitor Record Header
 NAME - MRIODDEV
 DESCRIPTIVE NAME - Monitor Sample Record
                    Domain 6 - I/O Domain
                    Record 3 - Device Activity
 DESCRIPTION - Describes I/O activities of a real device.  A separate
               record is generated for each online device that is
               enabled for monitoring.
 NOTES:
   - Fields labeled by the prefix, 'IODDEV_HF', are high-frequency
     counters.
   - When a virtual machine owning the device uses SIE ASSIST, CP
     does not handle the normal I/O and cannot update the RDEV
     counters.  Therefore, for a device that had been in SIE ASSIST,
     some RDEV or high-frequency counters may not correctly reflect
     real device activity.
   - "SCM Facility Data." Data obtained from the Subchannel
     Management Facility.  Not valid if the device was in SIE ASSIST
     and the V=R specifies that an Alternate Measurement Block is to
     be used.  (Note: this data will always be valid for a 370 V=R
     guest since VM/370 does not support Alternate Measurement Block)
   - "SIE ASSIST Activity Data." This data indicates how often and
     for how long the device had been in each respective state.
     There may be situations that would cause the device to be
     pulled out of SIE ASSIST and later put back in it.  Some
     devices may take longer than others to get out of SIE ASSIST.
     This can degrade the performance of the preferred guest.
     SIE ASSIST Activity Data is valid only for devices that are
     eligible for SIE ASSIST, indicated by IODDEV_VDEVIOP1.
     A SIE Assisted (I/O Assisted) device must be in one of three
     states: OUT, IN, LEAVING assist.  For each state a count of
     transitions into the state and a count of accumulated time in
     the state are kept.  However, since the time accumulator can
     only be updated when a device changes states, the accumulators
     reported in this monitor record (IODDEV_VIUTIMOT,
     IODDEV_VIUTIMIN, and IODDEV_VIUTIMLV) do not include time for
     the state the device is in when the monitor record is created.
     To determine the unassigned time, calculate the delta of the
     MRHDRTOD and IODDEV_VIUSTAMP.  This delta should be converted
     to microseconds and then added to the accumulator for the
     state indicated by the  IODDEV_VIUSTATE field.


MRIODDEV Control Block Contents

Offsets
Dec Hex  Type       Len  Name (Dim)          Description
 
  0   0  Structure  200  IODDEV              
  0   0  Character    0  IODDEV_MRHDR        Record header. See MRRECHDR for
                                             details.
  0   0  Character   20  MRHDR               
  0   0  Unsigned     2  MRHDRLEN            record length in bytes
  2   2  Unsigned     2  MRHDRZER            field of zeros
  4   4  Unsigned     1  MRHDRDM             domain identifier
  5   5  Unsigned     1  *                   
  6   6  Unsigned     2  MRHDRRC             record identifier
  8   8  Character    8  MRHDRTOD            Time at which this record was
                                             built. In time-of-day (TOD) clock
                                             format. See IBM System 370 XA
                                             Principle of Operation for
                                             explanation of format.
 16  10  Character    4  *                   
 20  14  Character    0  MRHDR_END           End of header
 20  14  Bitstring    1  IODDEV_RDEVAFLG     Device allocation flag
 21  15  Bitstring    1  IODDEV_RDEVLPM      logical path mask -logically
                                             available channel paths to this
                                             device
 22  16  Bitstring    1  IODDEV_VDEVIOP1     SIE ASSIST flags
          1... ....      IODDEV_VDEVIOPX     Eligible for SIE ASSIST to XA
                                             guest
          .1.. ....      IODDEV_VDEVIOP3     Eligible for SIE ASSIST to 370
                                             guest
          ..1. ....      *                   
          ...1 ....      *                   
          .... 1...      *                   
          .... .1..      *                   
          .... ..1.      *                   
          .... ...1      *                   
 23  17  Bitstring    1  IODDEV_CALFLAG1     Flags byte.
          1... ....      IODDEV_CALMDCNO     Device is not eligible for
                                             minidisk cache.
          .1.. ....      IODDEV_CALMDCDN     Caching on for this device,
                                             except for minidisks that are
                                             explicitly set off.
          ..1. ....      IODDEV_CALMDCDF     Caching off for this device,
                                             except for minidisks that are
                                             explicitly set on.
          ...1 ....      IODDEV_CALMDCOF     Caching set off for this device.
          .... 1...      IODDEV_RDEVSHAR     DASD is shareable.
          .... .1..      IODDEV_CALSCMBK     RDEVMBLK is non-zero indicating
                                             that an SCMBK is assigned to this
                                             device
          .... ..1.      IODDEV_CALTHROT     Device belongs to throttle set.
          .... ...1      *                   
 24  18  Unsigned     4  IODDEV_RDEVSID      host subchannel I.D. number
                                             defined at initialization
 28  1C  Character    8  IODDEV_RDEVCHPS     The eight channel path IDs
                                             available to access a device
 36  24  Character    6  IODDEV_RDEVSER      DASD volume serial identifier
 42  2A  Character    8  IODDEV_CALUSER      Userid of current owner (for
                                             dedicated devices only)
 50  32  Unsigned     2  IODDEV_RDEVLCNT     Cardinal count of minidisks
                                             defined on all or any part of this
                                             real DASD volume
 52  34  Unsigned     2  IODDEV_SCMSSCH      SCM Facility Data (see notes in
                                             prolog). Cumulative count of SSCHs
                                             and RSCHs for this device. This
                                             value may be wrapped when format-1
                                             measurement blocks are being used
                                             (MTRSYS_CALFLG2 = x'80').
 54  36  Unsigned     2  IODDEV_SCMCOUNT     SCM Facility Data (see notes in
                                             prolog). Cumulative sample count.
                                             Incremented whenever any
                                             measurement fields are updated.
                                             This value may be wrapped when
                                             format-1 measurement blocks are
                                             being used (MTRSYS_CALFLG2 =
                                             x'80').
 56  38  Unsigned     4  IODDEV_SCMCNTIM     SCM Facility Data (see notes in
                                             prolog). The time the device is
                                             connected to the channel. This is
                                             the sum of time intervals measured
                                             whenever the device is logically
                                             connected to the channel path for
                                             purposes of transferring
                                             information between it and the
                                             channel subsystem.
 60  3C  Unsigned     4  IODDEV_SCMFPTIM     SCM Facility Data (see notes in
                                             prolog). Device function pending
                                             time, the time interval between
                                             acceptance of the start function
                                             at the subchannel and acceptance
                                             of the first command associated
                                             with the initiation of
                                             channel-program execution at the
                                             device.
 64  40  Unsigned     4  IODDEV_SCMDDTIM     SCM Facility Data (see notes in
                                             prolog). Device disconnect time.
                                             The sum of the time intervals
                                             measured whenever the device is
                                             logically disconnected from the
                                             channel subsystem while the
                                             subchannel is active
 68  44  Unsigned     4  IODDEV_HFRDEVCT     Number of high frequency samples
                                             done
 72  48  Unsigned     4  IODDEV_HFCTIO       High-frequency Count. Number of
                                             SSCH, HSCH, and CSCH I/O requests
                                             queued, excluding the active
                                             request. RDEVCTIO
 76  4C  Unsigned     4  IODDEV_RDEVCTSR     Cumulative count of SSCHs done
                                             for error recovery purposes
 80  50  Unsigned     4  IODDEV_RDEVRCWH     Cumulative count of real reserve
                                             CCWs that have been sent to a
                                             device and are held immediately
 84  54  Unsigned     4  IODDEV_RDEVRCWP     Cumulative count of real reserve
                                             CCWs that have been sent to a
                                             device and are held pending
 88  58  Character    8  IODDEV_RDEVRTPD     Cumulative amount of real time a
                                             real reserve CCW is held pending
 96  60  Unsigned     4  IODDEV_RDEVCTSI     Cumulative count of solicited
                                             interrupts for this device
100  64  Unsigned     4  IODDEV_RDEVCTUI     Cumulative count of unsolicited
                                             interrupts for this device
104  68  Unsigned     4  IODDEV_RDEVMICT     Cumulative count of missing
                                             interrupts detected for this
                                             device. Incremented only when the
                                             SET MITIME command is active for
                                             this device
108  6C  Unsigned     4  IODDEV_RDEVCTRG     Cumulative count of RDEV lock
                                             requests granted immediately for
                                             this device
112  70  Unsigned     4  IODDEV_RDEVCTRD     Cumulative count of RDEV lock
                                             requests that were deferred for
                                             this device
116  74  Unsigned     4  IODDEV_RDEVSKCT     Cumulative count of DASD access
                                             arm position changes (Seek I/O)
                                             executed on this device. NOTE:
                                             accuracy is not guaranteed since
                                             counts may be skipped on
                                             multi-track operations on a cache
                                             control unit.
120  78  Unsigned     4  IODDEV_RDEVSKSM     Cumulative amount of DASD access
                                             arm movement (displacements). This
                                             is the sum of absolute
                                             differences, in cylinders, between
                                             successive Seeks.
124  7C  Unsigned     4  IODDEV_RDEVWRCT     Cumulative number of WRITE
                                             channel programs that have
                                             occurred on this device
128  80  Unsigned     4  IODDEV_RDEVRDCT     Cumulative number of READ
                                             channel programs that have
                                             occurred on this device
132  84  Unsigned     4  IODDEV_RDEVMCIA     Cumulative count of SSCH's
                                             avoided due to Minidisk Cache read
                                             hit
136  88  Unsigned     4  IODDEV_VIUCNTIN     SIE ASSIST Activity Data (see
                                             notes in prolog). Cumulative count
                                             of times the device was in SIE
                                             ASSIST.
140  8C  Unsigned     4  IODDEV_VIUTIMIN     SIE ASSIST Activity Data (see
                                             notes in prolog). Cumulative time,
                                             in micro seconds, spent in SIE
                                             ASSIST, including getting there.
                                             Accumulated after the device
                                             starts to leave SIE ASSIST (e.g.,
                                             it stays zero until after the
                                             device leaves SIE ASSIST for the
                                             first time). This field will wrap
                                             around after a total of about 71
                                             minutes (1.1 hours).
144  90  Unsigned     4  IODDEV_VIUCNTLV     SIE ASSIST Activity Data (see
                                             notes in prolog). Cumulative count
                                             of times the device started to
                                             leave SIE ASSIST.
148  94  Unsigned     4  IODDEV_VIUTIMLV     SIE ASSIST Activity Data (see
                                             notes in prolog). Cumulative time,
                                             in mirco seconds, spent in the
                                             process of leaving SIE ASSIST.
                                             Accumulated after the device has
                                             completed the process (e.g., it
                                             stays zero until after the device
                                             is out of SIE ASSIST for the first
                                             time). This field will wrap around
                                             after a total of about 71 minutes
                                             (1.1 hours).
152  98  Unsigned     4  IODDEV_VIUCNTOT     SIE ASSIST Activity Data (see
                                             notes in prolog). Cumulative count
                                             of times the device is out of SIE
                                             ASSIST. Initialized to one.
156  9C  Unsigned     4  IODDEV_VIUTIMOT     SIE ASSIST Activity Data (see
                                             notes in prolog). Cumulative time,
                                             in micro seconds, spent outside of
                                             SIE ASSIST. Accumulated after the
                                             device has gone into SIE ASSIST
                                             (e.g., it stays zero until after
                                             the first time the device goes
                                             into SIE ASSIST). This field will
                                             wrap around after a total of about
                                             71 minutes (1.1 hours).
160  A0  Unsigned     4  IODDEV_SCMDATIM     SCM Facility Data (see notes in
                                             prolog). Device-active-only time.
                                             The sum of the time intervals when
                                             the subchannel is device-active
                                             but not subchannel-active at the
                                             end of an I/O operation or chain
                                             of I/O operations initiated by
                                             START SUBCHANNEL.
164  A4  Character    8  IODDEV_VIUSTAMP     SIE ASSIST Activity Data (see
                                             notes in prolog). Time stamp of
                                             last transition between I/O Assist
                                             states.
172  AC  Bitstring    1  IODDEV_VIUSTATE     SIE ASSIST Activity Data (see
                                             notes in prolog). VDEV state in
                                             I/O Assist. X'00' = device is OUT
                                             of Assist, X'01' = device is IN
                                             Assist, X'02' = device is LEAVING
                                             Assist
173  AD  Character    3  *                   Reserved and available for IBM
                                             use.
176  B0  Unsigned     4  IODDEV_THRDLYS      Cummulative count of the number
                                             of times I/O was delayed for a
                                             throttled device.
180  B4  Unsigned     4  IODDEV_SCMCQTIM     SCM Facility Data (see notes in
                                             prolog). Control Unit Queuing
                                             time. The sum of the time
                                             intervals measured by the control
                                             unit whenever the device is
                                             logically disconnected from the
                                             channel subsystem during an I/O
                                             operation while the device is busy
                                             with an operation initiated from a
                                             different system.
184  B8  Unsigned     4  IODDEV_SCMDBTIM     SCM Facility Data (see notes in
                                             prolog). Accumulated device-busy
                                             time. The sum of the time
                                             intervals when the subchannel is
                                             device busy during an attempt
                                             initiate a start function or
                                             resume function at the subchannel.
188  BC  Unsigned     4  IODDEV_SCMIRTIM     SCM Facility Data (see notes in
                                             prolog). Accumulated initial-
                                             command-response time. The
                                             initial-command-response time for
                                             a start or resume function is the
                                             time interval beginning from when
                                             the first command of the channel
                                             program is sent to the device
                                             until the device indicates it has
                                             accepted the command.
192  C0  Unsigned     4  IODDEV_SCGSSCH      SCM Facility Data (see notes in
                                             prolog). Cumulative count of SSCHs
                                             and RSCHs for this device. This is
                                             the fullword count which is stored
                                             when format-1 measurement blocks
                                             are being used (MTRSYS_CALFLG2 =
                                             x'80').
196  C4  Unsigned     4  IODDEV_SCGCOUNT     SCM Facility Data (see notes in
                                             prolog). Cumulative sample count.
                                             Incremented whenever any
                                             measurement fields are updated.
                                             This is the fullword count which
                                             is stored when format-1
                                             measurement blocks are being used
                                             (MTRSYS_CALFLG2 = x'80').
200  C8  Character    0  IODDEV_END          

MRIODDEV Cross Reference

                      Hex           Hex
Name                 Offset Length Value
 
IODDEV                  0    200
IODDEV_CALFLAG1        17      1
IODDEV_CALMDCDF        17           20
IODDEV_CALMDCDN        17           40
IODDEV_CALMDCNO        17           80
IODDEV_CALMDCOF        17           10
IODDEV_CALSCMBK        17           04
IODDEV_CALTHROT        17           02
IODDEV_CALUSER         2A      8
IODDEV_END             C8      0
IODDEV_HFCTIO          48      4
IODDEV_HFRDEVCT        44      4
IODDEV_MRHDR            0      0
IODDEV_RDEVAFLG        14      1
IODDEV_RDEVCHPS        1C      8
IODDEV_RDEVCTRD        70      4
IODDEV_RDEVCTRG        6C      4
IODDEV_RDEVCTSI        60      4
IODDEV_RDEVCTSR        4C      4
IODDEV_RDEVCTUI        64      4
IODDEV_RDEVLCNT        32      2
IODDEV_RDEVLPM         15      1
IODDEV_RDEVMCIA        84      4
IODDEV_RDEVMICT        68      4
IODDEV_RDEVRCWH        50      4
IODDEV_RDEVRCWP        54      4
IODDEV_RDEVRDCT        80      4
IODDEV_RDEVRTPD        58      8
IODDEV_RDEVSER         24      6
IODDEV_RDEVSHAR        17           08
IODDEV_RDEVSID         18      4
IODDEV_RDEVSKCT        74      4
IODDEV_RDEVSKSM        78      4
IODDEV_RDEVWRCT        7C      4
IODDEV_SCGCOUNT        C4      4
IODDEV_SCGSSCH         C0      4
IODDEV_SCMCNTIM        38      4
IODDEV_SCMCOUNT        36      2
IODDEV_SCMCQTIM        B4      4
IODDEV_SCMDATIM        A0      4
IODDEV_SCMDBTIM        B8      4
IODDEV_SCMDDTIM        40      4
IODDEV_SCMFPTIM        3C      4
IODDEV_SCMIRTIM        BC      4
IODDEV_SCMSSCH         34      2
IODDEV_THRDLYS         B0      4
IODDEV_VDEVIOPX        16           80
IODDEV_VDEVIOP1        16      1
IODDEV_VDEVIOP3        16           40
IODDEV_VIUCNTIN        88      4
IODDEV_VIUCNTLV        90      4
IODDEV_VIUCNTOT        98      4
IODDEV_VIUSTAMP        A4      8
IODDEV_VIUSTATE        AC      1
IODDEV_VIUTIMIN        8C      4
IODDEV_VIUTIMLV        94      4
IODDEV_VIUTIMOT        9C      4
MRHDR                   0     20
MRHDR_END              14      0
MRHDRDM                 4      1
MRHDRLEN                0      2
MRHDRRC                 6      2
MRHDRTOD                8      8
MRHDRZER                2      2

This information is based on z/VM V4R4.0.
Last updated on 22 Jul 2003 at 15:04:23.
Copyright IBM Corporation, 1990, 2003