SY2 trace flow

Figure 1 and Figure 2 contain the SY2 trace information found in SYSOMVS component trace formatted with CTRACE COMP(SYSOMVS) FULL.

Figure 1 describes the server side XCF SRB processing by first queuing the request (BPXNXMSG), and then having a worker task pick up that piece of work for subsequent processing (BPXNXWRK).

As noted with an *, the Request-ID is used to cross reference the individual trace entries.

When a SYSNAME field is included in a trace entry, the ASID / TCB information actually describes the client side requester information. The SYSNAME field describes the originating system. The highlighted field with an & is the TCB address of the worker task resident in the server system.

Figure 1. SY2 Trace Flow: Part 1

SYSNAME   MNEMONIC  ENTRY ID    TIME STAMP     DESCRIPTION
-------   --------  --------  ---------------  -------------
SY2       XCF       0D690402  18:14:14.553698  NXMSG-->XCF MESSAGE SRB EXIT

    ASID..000E      USERID....OMVS      STACK@....25389F28
    TCB...00000000  EUID......00000000  SYSCALL...00000000
   +0000  D9C5C3E5  D4600201  009E04A0  002580E0  | RECVM-.........\ |
   +0010  00030000 !0A010014 *01170BD4 $0013C000  | ...........M..{. |
   +0020  01000001  000A0001  00008178  01FF0006  | ..........a..... |
   +0030  40060098  80000009  00000000  00000000  |  ..q............ |
   +0040  00000000  00000000  4F4F4F4F            | ........||||     |

SY2       XCF       0D6D0403  18:14:14.553715  NXWRK-->XCF WORKER TASK TRACE

   #ASID..0025      USERID....OMVS      STACK@....25CF0000
   #TCB...009E04A0  EUID......0000000B
    FCODE.0003      SYSNAME...SY1
   +0000  E6D6D9D2  3000022C &009D6C68 !0A010014  | WORK......%..... |
   +0010 *01170BD4 $0013C02C  01000001  000A0001  | ...M..{......... |
   +0020  01FF0006  40060098  000080E0  009E04A0  | .... ..q...\.... |
   +0030  00250003  00000000  00000000  00000000  | ................ |
   +0040  00000000                                | ....             |

# - ASID / TCB of requester    & - Real OMVS resident worker TCB
$ - Block #, Index into NXRQ   ! - HFS function being requested
* - Unique Request-ID          % - Indicates ASID/TCB remapped to requester

Figure 2 describes the response arriving on the client system. First the XCF SRB (BPXNXMSG) processes the incoming response to cause the client task to be activated. And then the target task (no longer remapped) wakes up, and in this case explicitly frees the resources that were allocated to it as part of the XCF message processing.

Figure 2. SY2 Trace Flow: Part 2

SYSNAME   MNEMONIC  ENTRY ID    TIME STAMP     DESCRIPTION
-------   --------  --------  ---------------  -------------
SY2       XCF       0D890407  18:14:14.553881  XCF BUFFER I/O TRACE

   #ASID..0025      USERID....OMVS      STACK@....25CF0000
   #TCB...009E04A0  EUID......0000000B
    FCODE.0003     %SYSNAME...SY1
   +0000  E2C5D5C4  80180101  01000001  000A0001  | SEND............ |
   +0010  B2DBC852  29114142 @7F636AD8  401FB000  | ..H....."..Q ... |
   +0020  01FF0006  00000118  C6000000            | ........F...     |

SY2       XCF       0D6F0401  18:14:14.554039  NXMSO-->XCF MESSAGE OUT

   #ASID..0025      USERID....OMVS      STACK@....25CF0000
   #TCB...009E04A0  EUID......0000000B
    FCODE.0003     %SYSNAME...SY1
   +0000  D9C5E2D7  202002D3 !0A010014 *01170BD4  | RESP...L.......M |
   +0010 $0013402C  01000001  000A0001  00002BBC  | .. ............. |
   +0020 @7F636AD8  00000080  00000000  00000000  | "..Q............ |
   +0030  0D6F0000  00030000  009D6C68  00000000  | .?........%..... |
   +0040  253A4088  00000000  00000000            | .. h........     |

# - ASID / TCB of requester    @ - Buffer address containing request
$ - Block #, Index into NXRQ   ! - HFS function being requested
* - Unique Request-ID          % - Indicates ASID/TCB remapped to requester