Stopping GTF

You can enter the STOP command at any time during GTF processing. The amount of time you let GTF runs depends on your installation and the problem you are trying to capture, but a common time is between 15 and 30 minutes.

If you are running GTF to gather information related to a problem for which a SLIP trap has been defined, you can instruct SLIP to stop all instances of GTF when the trap conditions are satisfied. For additional information, see the SLIP Command documentation in z/OS MVS System Commands.

To stop GTF processing, enter the STOP command. The STOP command must include either the GTF identifier specified in the START command, or the device number of the GTF trace data set if you specified MODE=EXT or MODE=DEFER to direct output to a data set. If you have not specified the GTF identifier in the START command, then those instances of GTF will have the same identifier: the volume serial number.

If you are not sure of the identifier or the device number of the trace data set, enter the following command:

DISPLAY A,LIST

Figure 1 shows the output produced by the DISPLAY A,LIST command. In this example, the identifier for GTF is EVENT1.

Figure 1. Example: recognizing GTF identifier in DISPLAY A,LIST output

IEE114I 14.51.49 1996.181 ACTIVITY     FRAME LAST   F      E   SYS=SY1
 JOBS     M/S    TS USERS    SYSAS    INITS   ACTIVE/MAX VTAM     OAS
00000    00003    00000      00016    00000    00000/00000       00000
 LLA      LLA      LLA      NSW  S  VLF      VLF      VLF      NSW  S
 JES2     JES2     IEFPROC  NSW  S
 GTF      EVENT1   IEFPROC  NSW  S

You must enter the STOP command at a console with master authority. The general format of the STOP command is as follows:

{STOP|P} identifier

For example, to stop GTF for the identifier EVENT1 (as shown in Figure 1), enter the command:

STOP EVENT1

When the STOP command takes effect, the system issues message AHL006I. If the system does not issue message AHL006I, then GTF tracing continues, remaining active until a STOP command takes effect or the next initial program load (IPL). When this happens, you will not be able to restart GTF tracing. In this case, you can use the FORCE ARM command to stop GTF.

If there were several functions started with the same identifier on the START command, using the same identifier on the STOP command will stop all those functions.

If the volume serial number is used on the STOP command, all instances of GTF with trace data directed to a data set on that volume serial are stopped. This is independent of the identifier assigned to each instance of GTF.

For example, if three instances of GTF are active with the identifiers EX1, EX2, and EX3 directing trace data to different data sets to the same volume with volume serial number 1020, then the following command will stop all the 3 instances of GTF.

STOP 1020

See z/OS MVS System Commands for more information about the STOP and FORCE ARM commands.

You can also use an identifier to stop GTF. In this example, the following command starts GTF tracing with the identifier EXAMPLE and with trace data maintained in the GTF address space. The DSN keyword is entered to prevent allocation of an external trace data set as specified in the cataloged procedure.

  START GTF.EXAMPLE,,,(MODE=INT),DSN=NULLFILE

To stop GTF tracing, you would issue the following command:

  STOP EXAMPLE

In some instances, you may need to display the active jobs before stopping GTF. The example shown in Figure 2 starts GTF tracing with trace data recorded on an external device, data set GTF.TEST01. Another instance of GTF with an identifier EX1 is started with trace data directed to another data set on the same volume. Note that you do not have to specify MODE=EXT, because it is the default.

Figure 2. Example: Starting instances of GTF

S GTF,,,DSNAME=GTF.TEST01,VOLUME=SER=IPCS01,DISP=OLD
S GTF.EX1,DSNAME=GTF.TEST02,VOLUME=SER=IPCS01

Because it is not apparent which is the GTF recording device, you have to display active jobs with the DISPLAY A,LIST command before stopping GTF. In Figure 3, the device number for GTF is 0227.

Figure 3. Example: DISPLAY A,LIST command output

IEE114I 09.33.45 1996.183 ACTIVITY 951
 JOBS     M/S    TS USERS    SYSAS    INITS   ACTIVE/MAX VTAM     OAS
00001    00006    00001      00015    00002    00001/00300       00000
 LLA      LLA      LLA      NSW  S  VLF      VLF      VLF      NSW  S
 VTAM     VTAM     VTAM     NSW  S  JES2     JES2     IEFPROC  NSW  S
 TCAS     TCAS     TSO      OWT  S  SDJSST1B STEP1             OWT  J
GTF      0227     IEFPROC  NSW  SGTF      EX1      IEFPROC  NSW  S

If you only want to stop only the second instance of GTF, issue the following command:

STOP EX1

If you want to stop both instances, issue the following command:

STOP 227