Starting and stopping GFS trace
The following procedure explains how to request a GFS trace.
- 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.
- Ask the operator to enter the SET DIAG=xx command to activate GFS trace using the definitions in the DIAGxx parmlib member.
- 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
- To stop the GTF trace, ask the operator to enter a STOP procname command on the operator console.
- 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:
- See z/OS MVS Initialization and Tuning Reference for the syntax of the DIAGxx parmlib member.
- See z/OS MVS System Commands for the syntax of the SET and START commands.
- See The Generalized Trace Facility (GTF) for information about how to specify GTF EIDs.