Understanding the Program-to-Program Interface Trace Record

A PPI trace record is created for PPI request types 4, 9, 10, 12, 14, 22, and 23. Request types 1, 2, 3, and 24 run in the user address space. As a result, it is not possible for the PPI to trace these request types. To trace these request types, implement your own trace. The request types that are traced are grouped under various eye-catchers, including:
INIT
Request type 4 is traced under the INIT eye-catcher. The following fields are written for this trace record:
  • The eye-catcher (INIT)
  • The backward and forward pointers
  • The length of the trace record
  • A time stamp that indicates the time of the request
  • The receiver ID, including:
    • Receiver name
    • ASID
    • Address space control block (ASCB) address
    • TCB address
DISC
Request type 9 is traced under the DISC eye-catcher. The following fields are written for this trace record:
  • The eye-catcher (DISC)
  • The backward and forward pointers
  • The length of the trace record
  • A time stamp that indicates the time of the request
  • The receiver ID, including:
    • Receiver name
    • ASID
    • ASCB address
    • TCB address
ABND
The ABND eye-catcher indicates an abnormal end (abend) of a receiver with respect to the PPI. That is, the receiver disconnected from the PPI without issuing a request type 9 or 10. This can occur for several reasons. For example, this can happen if a user abended, the task ended without issuing a request type 9 or 10, or the SSI ended. The following fields are written for this trace record:
  • The eye-catcher (ABND)
  • The backward and forward pointers
  • The length of the trace record
  • A time stamp that indicates the time when the abend occurred
  • The receiver ID, including:
    • Receiver name
    • ASID
    • ASCB address
    • TCB address
DELT
Request type 10 is traced under the DELT eye-catcher. The following fields are written for this trace record:
  • The eye-catcher (DELT)
  • The backward and forward pointers
  • The length of the trace record
  • A time stamp that indicates the time the abend occurred
  • The receiver ID, including:
    • Receiver name
    • ASID
    • ASCB address
    • TCB address
SEND
Request types 12 and 14 are traced under the SEND eye-catcher. The following fields are written for this trace record:
  • The eye-catcher (SEND)
  • The backward and forward pointers
  • The length of the trace record
  • A time stamp that indicates the time of the request
  • The receiver ID, Including:
    • Receiver name
    • ASID
    • ASCB address
    • TCB address
  • Sender ID, including
    • Sender name
    • ASID
    • ASCB address
    • TCB address
  • Frame Number
  • The length of the buffer that was sent

The amount of buffer data copied from the buffer and sent is determined by the receiver's trace buffer size value.

RECV
Request type 22 is traced under the RECV eye-catcher. The following fields are written for this trace record:
  • The eye-catcher (RECV)
  • The backward and forward pointers
  • The length of the trace record
  • A time stamp that indicates the time of the request
  • The receiver ID, including:
    • Receiver name
    • ASID
    • ASCB address
    • TCB address
  • Sender ID, including:
    • Sender name
    • ASID
    • ASCB address
    • TCB address
  • Frame Number
  • The length of the buffer that was received

The frame number matches the frame number of the SEND trace record created when the buffer is sent. The amount of buffer data copied from the buffer received is determined by the receiver's trace buffer size value.

PURG
Request type 23 is traced under the PURG eye-catcher. The following fields are written for this trace record:
  • The eye-catcher (PURG)
  • The backward and forward pointers
  • The length of the trace record
  • A time stamp that indicates the time of the request
  • The receiver ID, including:
    • Receiver name
    • ASID
    • ASCB address
    • TCB address
  • Sender ID, including:
    • Sender name
    • ASID
    • ASCB address
    • TCB address
  • Frame Number
  • The length of the buffer that was purged

The frame number matches the frame number of the SEND trace record that is created when the buffer is sent. The amount of buffer data copied from the buffer that is purged is determined by the receiver's trace buffer size value.

ERR
This PPI trace record is written only when an error occurs while the PPI is allocating a trace record for a GTF trace or, if the GTF becomes disabled. The following fields are written for this trace record:
  • The eye-catcher (ERR)
  • The length of the trace record
  • A time stamp that indicates the time of the error
  • The frame number

The frame number contains the number of trace records lost.