Starting and stopping GFS trace

The following procedure explains how to request a GFS trace.
  1. In the DIAGxx parmlib member, set the VSM TRACE GETFREE parameter to ON and define the GFS trace control data.
    Example: DIAGxx parmlib member for starting GFS tracing: The following DIAGxx parmlib member starts GFS trace and limits the trace output to requests to obtain or release virtual storage that is 24 bytes long and resides in address spaces 3, 5, 6, 7, 8 and 9:
        VSM TRACE GETFREE (ON)
                  ASID (3, 5-9)
                  LENGTH (24)
                  DATA (ALL)

    You will need another DIAGxx parmlib member defined to stop GFS tracing. See 5.

  2. Ask the operator to enter the SET DIAG=xx command to activate GFS trace using the definitions in the DIAGxx parmlib member.
  3. Start a GTF trace (ask the operator to enter a START membername command on the operator console). membername is the name of the member that contains the source JCL (either a cataloged procedure or a job). Tell the operator to specify a user event identifier X'F65' to trace GTF user trace records.
    Example: Starting a GTF trace for GFS data: In the following example, the operator starts GTF tracing with cataloged procedure GTFPROC to get GFS data in the GTF trace output. The contents of cataloged procedure GTFPROC are as follows:
    //GTF     PROC MEMBER=GTFPROC
    //* Starts GTF
    //IEFPROC EXEC PGM=AHLGTF,REGION=32M,
    //  PARM='MODE=EXT,DEBUG=NO,TIME=YES,BLOK=40K,SD=0K,SA=40K'
    //IEFRDER DD DSN=D31POOL.PJREDGTF.TRACE,
    //           DISP=SHR,UNIT=3380,VOL=SER=CTDSD1

    The operator then replies to messages AHL100A with the USRP option. When message AHL101A prompts the operator for the keywords for option USRP, the operator replies with USR=(F65) to get the GFS user trace records in the GTF trace output.

    START GTFPROC
    
    00 AHL100A SPECIFY TRACE OPTIONS
    
    REPLY 00,TRACE=USRP
    
    01 AHL101A SPECIFY TRACE EVENT KEYWORDS--USR=
    
    REPLY 01,USR=(F65)
    
    02 AHL102A CONTINUE TRACE DEFINITION OR REPLY END
    
    REPLY 02 END
    
    AHL103I TRACE OPTIONS SELECTED--USR=(F65)
    
    03 AHL125A RESPECIFY TRACE OPTIONS OR REPLY U
    
    REPLY 03,U
  4. To stop the GTF trace, ask the operator to enter a STOP procname command on the operator console.
  5. To stop GFS trace, create a DIAGxx parmlib member with VSM TRACE GETFREE(OFF) and have the operator enter a SET DIAG=xx command.
    Example: DIAGxx parmlib member for stopping GFS tracing: The following DIAGxx parmlib member stops GFS trace:
        VSM TRACE GETFREE (OFF)
For additional information, see the following references: