Programming Interface Information:
This information is NOT intended to be
used as Programming Interfaces of z/VM.

SRXBK

Prolog  

Control Block Contents  
   SRXBK DSECT

Storage Layout  

Cross Reference (Contains links to field and bit definitions)  


SRXBK Prolog

 NAME       : HCPSRXBK
 DESCRIPTION: System Resource Management block extensions
 DSECT      : SRXBK
 FUNCTION   : HCPSRXBK contains original SRMBK fields which are
              duplicated for Mixed-Engine partitions.  These
              fields are used by the System Resource Manager
              (Scheduler) in the maintainance of user lists and
              calculation of various scheduling parameters.
 LOCATED BY : SRMXTBL table of SRXBK pointers by processor
              type
 CREATED BY : HCPIST during system initialization
 DELETED BY : Never deleted
 REFERENCES : None
 SERIALIZED : Scheduler lock (SRMSLOCK)
 NOTES      : An SRXBK exists for
              each processor type that is valid in a Mixed-Engines
              configuration.  Prior to Mixed-Engines support, these
              fields were global scheduler fields.  Now they must
              be viewed as valid for a particular processor type
              only.  For example, when processing the SRXBK for
              type zAAP, SRXMXSHR is the largest SHARE of system
              that can be delivered to a single VMDBK of type
              zAAP.

 

SRXBK Control Block Content


SRXBK DSECT

Hex   Dec Type/Val   Lng Label (dup)    Comments
---- ---- --------- ---- -------------- --------
0000    0 Structure      SRXBK          System Resource Management block
                                        extensions
0000    0 Signed       4 SRXDLSCN       Dispatch list scan header. This
                                        is the point at which HCPSTK's
                                        LINKDS subroutine is to begin
                                        scanning the dispatch list for an
                                        insertion point whenever adding a
                                        user
0004    4 Address      4 SRXDLADD       Pointer to the last VMDBK added
                                        to the D-list ahead of ATOD. Used
                                        to reduce scans in the list.
             Timing Parameters
             NOTES      : The assembler construct 'FL8S12' is used to
             generate a fixed-point number which represents a
             time value (in microseconds) in TOD clock format
             or CPU timer format.  'FL8S12E6' is used when
             specifying a time value in seconds (rather than
             microseconds).
0008    8 Signed       8 SRXHIDSP       Dispatching priority of the
                                        highest priority user on the
                                        dispatch list at the time of the
                                        last major reshuffle (HCPDSBRV)
                                        less an adjustment interval to
                                        allow for continuing transactions
                                        returning to the dispatch list.
                                        The highest priority user has the
                                        lowest value of VMDDPRTY. This
                                        field is the basis for computing
                                        field DSVPRIOR in the PLDV.
                                        DSVPRIOR = VMDDPRTY - SRXHIDSP.
                                        (at least 32 bits of the result).
0010   16 Signed       8 SRXATOD        Artificial TOD. This TOD only
                                        advances at the rate the system
                                        is running user work.
0018   24 Signed       4 SRXTOTLS (0)   An equate used as an index base
                                        to reference one of the next two
                                        fields, srmreldl and srmabsdl.
                                        Code depends on these two fields
                                        being fullwords and following IN
                                        THE GIVEN ORDER.
0018   24 Signed       4 SRXRELDL       The sum of the relative shares of
                                        all RELATIVE share holders
                                        (excluding dedicated VMDBKs)
                                        currently in the dispatch list.
                                        This field is protected by the
                                        scheduler lock.
001C   28 Signed       4 SRXABSDL       The sum of the absolute shares of
                                        all VMDBKs (excluding dedicated
                                        VMDBKs) currently in the dispatch
                                        list. This field is protected by
                                        the scheduler lock.
0020   32 Signed       4 SRXTOTDE (0)   An equate used as an index base
                                        to reference one of the next two
                                        fields, srmrelde and srmabsde.
                                        Code depends on these two fields
                                        being fullwords and following in
                                        the given order.
0020   32 Signed       4 SRXRELDE       The sum of the relative shares of
                                        all relative share holders
                                        currently in the eligible and
                                        dispatch list. This field is
                                        protected by the scheduler lock.
0024   36 Signed       4 SRXABSDE       The sum of the absolute shares of
                                        all VMDBKs currently in the
                                        eligible and dispatch list. This
                                        field is protected by the
                                        scheduler lock.
0028   40 Signed       2 SRXNCPUA       The number of CPUs available to
                                        schedule time on for
                                        non-dedicated users. This field
                                        is protected by the scheduler
                                        lock.
002A   42 Signed       2 *              Reserved for future IBM use
002C   44 Address      4 SRXLLIST       Anchor for the limit-list.
                                        Contains address of 1st VMDBK in
                                        list, or zero if list is empty.
                                        VMDBKs are forward and backward
                                        chained via VMDLFPNT & VMDLBPNT.
0030   48 Dbl-Word     8 SRXATODD       A timestamp (TOD). The deadline
                                        for current ATOD-interval to end.
                                        Each CPU will copy this into its
                                        PFXATODD. But PFXATODD will often
                                        be an iteration behind SRXATODD.
0038   56 Dbl-Word     8 SRXCHKIN       A timestamp (TOD). Time when the
                                        first-checker CPU last checked in
                                        (to start current ATOD-interval).
                                        Equals PFXCHKIN of first-checker.
0040   64 Dbl-Word     8 SRXCHKTW       A timestamp (TOD). Time when the
                                        tracked-wait masks (SRXASKT1 and
                                        SRXASKT2) should next be checked.
                                        (Set to something like TOD+10ms.)
0048   72 Signed       8 SRXATOD2       Artificial TOD2. This TOD
                                        advances with each CPU's user
                                        time and each CPU's wait time.
0050   80 Dbl-Word     8 SRXASKTW       Mask has a bit for each logical
                                        CPU. Bit is on if the CPU is
                                        currently in "tracked-wait" mode.
0058   88 Dbl-Word     8 SRXASKT1       Mask has a bit for each logical
                                        CPU. Bit is on if CPU performed
                                        an ATOD-check-in since mask was
                                        last reset (as timed by
                                        SRMASKTM).
0060   96 Dbl-Word     8 SRXASKT2       Mask has a bit for each logical
                                        CPU. Bit is on if CPU performed
                                        an ATOD-check-in during previous
                                        interval (as timed by SRMASKTM).
0068  104 Signed       4 SRXTRKCT       Count of tracked-wait-mode CPUs.
006C  108 Address      4 SRXLODSP       Pointer to the VMDBK just above
                                        ATOD in the dispatch list. It is
                                        advanced only when ATOD is up-
                                        dated, and so may not always
                                        point to quite the last VMDBK.
                                        PURPOSE: Save scanning overhead
                                        when locating VMDBKs which have
                                        aged out of the SRXCTHRU bunch.
       SRXRTHRU and SRXCTHRU are two tables, used in normalizing
       users' VMDRTHRUs.  (VMDRTHRU is the user's "required
       throughput" i.e., his SHARE after it has been adjusted to
       compensate him for any delay in the eligible list.)
0070  112 Signed       4 SRXRTHRU (0)   Start of array (table) of sums of
                                        VMDRTHRU values for all VMDBKs in
                                        the dispatch list.
0070  112 Signed       4 SRXRTHRN       Total VMDRTHRU of VMDBKs in the
                                        dispatch list which are not cur-
                                        rently hitting their max-SHAREs.
0074  116 Signed       4 SRXRTHRL       Total VMDRTHRU of VMDBKs in the
                                        dispatch list which are current-
                                        ly hitting their max-SHAREs.
                                        (LIMITed and hitting the limit.)
0078  120 Signed       4 SRXRTHRZ (0)   End of array (table).
             Notes      : SRXRTHRN and SRXRTHRL must have the same
             offsets within the SRXRTHRU array as SRXCTHRN
             and SRXCTHRL have in the SRXCTHRU array.
0078  120 Signed       4 SRXCTHRU (0)   Start of array (table) of sums of
                                        VMDRTHRU values of compute- bound
                                        VMDBKs (literally, VMDBKs below
                                        ATOD) in the dispatch list.
0078  120 Signed       4 SRXCTHRN       Total VMDRTHRU of compute-bound
                                        VMDBKs not hitting max-SHARE.
007C  124 Signed       4 SRXCTHRL       Total VMDRTHRU of compute-bound
                                        VMDBKs hitting max-SHARE.
0080  128 Signed       4 SRXCTHRZ (0)   End of array (table).
             General Data Fields
0080  128 Signed       4 SRXMXSHR       Largest SHARE of system that can
                                        be delivered to a single VMDBK.
                                        It is the reciprocal of SRXNCPUA.
                                        (E.g., 0.25 on a 4-way system.)
0084  132 Signed       4 SRXLLCNT       Count of adds to the limit-list.
                                        This count is only approximate,
                                        it does not include adds result-
                                        from virtual-MP priority drop.
0088  136 Signed       4 SRXCONLL       Count of users actually ON the
                                        Limit List. This count is
                                        serialized by the scheduler lock.
008C  140 Address      4 SRXDVLST       Anchor into the linked list of
                                        PLDV's linked by DSVNXTDV.
      The following field is a bit masks for which each real
      processor has a corresponding unique bit.
0090  144 Dbl-Word     8 SRXLCPUA       Mask containing the logical CPU
                                        ids (PFXLCPUA) of CPUs which are
                                        online and non-dedicated. (The
                                        counter SRXNCPUA should tell how
                                        many bits are on in SRXLCPUA.)
                                        See also SYSLCPUA, which is
                                        similar, but shows dedicated CPUs
                                        and also offline CPUs whose
                                        prefix pages have not been freed.
0098  152 Address      4 SRXTRQWT       Points to TRQBK used to bring us
                                        out of wait state when it is time
                                        to dequeue VMDBKs from
                                        limit-list.
009C  156 Signed       4 *              Reserved for IBM use
          00000014       SRXSIZE        (*-SRXBK+7)/8 size in double
                                        words
          000000A0       SRXBSIZE       SRXSIZE*8 size in bytes

 

SRXBK Storage Layout

          
*** SRXBK - System Resource Management block extensions
*
*     +---------------------------+---------------------------+
*   0 |         SRXDLSCN          |         SRXDLADD          |
*     +---------------------------+---------------------------+
*   8 |                       SRXHIDSP                        |
*     +-------------------------------------------------------+
*  10 |                       SRXATOD                         |
*     +---------------------------+---------------------------+
*  18 |         SRXRELDL          |         SRXABSDL          |
*     +---------------------------+---------------------------+
*  20 |         SRXRELDE          |         SRXABSDE          |
*     +-------------+-------------+---------------------------+
*  28 |  SRXNCPUA   |/////////////|         SRXLLIST          |
*     +-------------+-------------+---------------------------+
*  30 |                       SRXATODD                        |
*     +-------------------------------------------------------+
*  38 |                       SRXCHKIN                        |
*     +-------------------------------------------------------+
*  40 |                       SRXCHKTW                        |
*     +-------------------------------------------------------+
*  48 |                       SRXATOD2                        |
*     +-------------------------------------------------------+
*  50 |                       SRXASKTW                        |
*     +-------------------------------------------------------+
*  58 |                       SRXASKT1                        |
*     +-------------------------------------------------------+
*  60 |                       SRXASKT2                        |
*     +---------------------------+---------------------------+
*  68 |         SRXTRKCT          |         SRXLODSP          |
*     +---------------------------+---------------------------+
*  70 |         SRXRTHRN          |         SRXRTHRL          |
*     +---------------------------+---------------------------+
*  78 |         SRXCTHRN          |         SRXCTHRL          |
*     +---------------------------+---------------------------+
*  80 |         SRXMXSHR          |         SRXLLCNT          |
*     +---------------------------+---------------------------+
*  88 |         SRXCONLL          |         SRXDVLST          |
*     +---------------------------+---------------------------+
*  90 |                       SRXLCPUA                        |
*     +---------------------------+---------------------------+
*  98 |         SRXTRQWT          |///////////////////////////|
*     +---------------------------+---------------------------+
*  A0
*
*** SRXBK - System Resource Management block extensions

 

SRXBK Cross Reference

Symbol         Dspl Value
-------------- ---- -----
SRXABSDE       0024
SRXABSDL       001C
SRXASKTW       0050
SRXASKT1       0058
SRXASKT2       0060
SRXATOD        0010
SRXATODD       0030
SRXATOD2       0048
SRXBSIZE       009C 000000A0
SRXCHKIN       0038
SRXCHKTW       0040
SRXCONLL       0088
SRXCTHRL       007C
SRXCTHRN       0078
SRXCTHRU       0078
SRXCTHRZ       0080
SRXDLADD       0004
SRXDLSCN       0000
SRXDVLST       008C
SRXHIDSP       0008
SRXLCPUA       0090
SRXLLCNT       0084
SRXLLIST       002C
SRXLODSP       006C
SRXMXSHR       0080
SRXNCPUA       0028
SRXRELDE       0020
SRXRELDL       0018
SRXRTHRL       0074
SRXRTHRN       0070
SRXRTHRU       0070
SRXRTHRZ       0078
SRXSIZE        009C 00000014
SRXTOTDE       0020
SRXTOTLS       0018
SRXTRKCT       0068
SRXTRQWT       0098

This information is based on z/VM V5R3.0. Last updated on 25 Jun 2007 at 17:32:39 EDT.
Copyright IBM Corporation, 1990, 2007