SirTune data collection under CMS

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As of the integration of the SirTune data collector with the &SIRMODS. (in &SIRMODS. version 6.9), how you invoke SirTune depends on its version.

Versions of SirTune after 1.5

The data collection portion of SirTune is part of the &SIRMODS. object. It also requires a load module called SIRTUNED, which runs in a separate service machine. The data collector becomes available once the &SIRMODS. is link edited into the Model 204 ONLINE module and once the SIRTUNED service machine is made available.

Invoking SirTune

To invoke SirTune, the EXEC that invokes the Model 204 load module should do so directly:

M204CMS M204ONLN ...

This statement differs from that required for version 1.5 and earlier of SirTune (which is described in Invoking the SIRTUNE module).

SirTune also requires the presence of a virtual machine running the SIRTUNED load module (as described in The SIRTUNED virtual machine). Then, if SirTune is authorized for use at your site, the SirTune data collector will be initialized,

If you are upgrading from an earlier version of SirTune, no changes are necessary to any SirTune DDs you were using. However, if you specified SIRTUNEI configuration statements for the data collector, the PGM statement is ignored, since SirTune no longer loads the Model 204 ONLINE load module.

If you want to prevent the SirTune data collector from being initialized, do the following:

  • Set the SIRTUNE parameter to 0.

    The SIRTUNE parameter, which controls whether the SirTune data collector is initialized at the start of a Model 204 run, can be set to either of these values:

    0Disables initialization of the integrated SirTune product for a particular run.
    1Enables initialization (this is the default).

    For example:

    M204CMS M204ONLN ( SIRTUNE 0 ...

Optional SirTune DD name

SirTune has the optional DD described below, for which a FILEDEF can be added to M204FDEF EXEC or any other EXEC invoked before the ONLINE module.

Note: The SIRTUNEO DD used in earlier versions of SirTune is obsolete in versions of SirTune after 1.5.

SIRTUNEI This optional DD contains configuration statements that alter the SirTune defaults.

These statements (SirTune configuration statements) allow control over the name of the allow control over the name of the Model 204 load module, the level of detail to which data is collected, the time intervals over which data is collected, the sampling rate, authorization to issue MODIFY commands, and more.

SIRTUNEI can have either fixed or variable format, and it can have any record length.

The following is a sample FILEDEF:

FILEDEF SIRTUNEI DISK SIRTUNE INPUT A

Version 1.5 or earlier of SirTune

The data collection portion of SirTune consists of a load module called SIRTUNE that runs in the Model 204 ONLINE virtual machine or virtual machines and another load module called SIRTUNED which runs in a separate service machine.

Invoking the SIRTUNE module

To have SirTune collect data for a particular ONLINE machine, do the following:

  1. Place the SIRTUNE load module on a minidisk accessible to the virtual machine running Model 204.
  2. Modify the EXEC that invokes Model 204 so that it invokes SIRTUNE instead.

    For example, to have SIRTUNE monitor an ONLINE that is invoked with

    M204CMS M204ONLN ( SYSOPT 155 LIBUFF 600

    change the line to read

    M204CMS SIRTUNE ( SYSOPT 155 LIBUFF 600

SIRTUNE will then invoke Model 204 collecting polling data as required.

SirTune data collection should have no significant impact on the performance of the ONLINE virtual machine.

If SIRTUNE is able to load Model 204 but cannot sample for some reason (including unknown Model 204 release, SirTune expiration, or operation on an unauthorized CPU), Model 204 will still proceed. This allows leaving SIRTUNE in place in your EXECs while a temporary problem is being solved.

Optional SIRTUNE DD names

The SIRTUNE load module has some optional DDs. FILEDEFs can be added for these DDs to M204FDEF EXEC or any other EXEC invoked before SIRTUNE. The optional DDs are:

SIRTUNEISee Optional SirTune DD name.
SIRTUNEOThis optional DD receives informational SIRTUNE messages. If this DD is not specified, SIRTUNE messages go to the virtual console. SIRTUNEO must have LRECL greater than or equal to 80.

The following is a sample FILEDEF:

FILEDEF SIRTUNEO FISK SIRTUNE LISTING A

The SIRTUNED virtual machine

SirTune requires the presence of a virtual machine running the SIRTUNED load module. It is recommended that this virtual machine be given the userid SIRTUNED. The installation tape contains a sample exec called SIRTUNED EXEC which can be used as PROFILE EXEC for this service machine.

This service machine communicates with all running ONLINE virtual machines running SirTune, saving their sample data to disk. Because of this, appropriate directory statements must be added to the CP directory to allow IUCV communications between the Model 204 virtual machines and the SIRTUNED virtual machine. The easiest way to accomplish this is by adding the IUCV ALLOW directory statement for user SIRTUNED.

The sample SIRTUNED EXEC invokes the SIRTUNED MODULE as follows:

'SIRTUNED';

To authorize users to issue commands to SIRTUNED via SMSG, list the authorized users after the SIRTUNED command. The userids in the list can contain wildcard characters. For example,

'SIRTUNED SYSOPER MARGE*';

authorizes userid SYSOPER and any userid begining with the characters MARGE to issue a command to SIRTUNED via SMSG. For more information on using wildcards in this list, see Sirtune statement wildcards.

SIRTUNED will use MSGNOH for its responses if it is authorized; otherwise it will use MSG.

It is generally not important to terminate the SIRTUNED service machine "cleanly" if the Model 204 virtual machines running SirTune are themselves terminated cleanly. However, if it becomes necessary to terminate the SIRTUNED service machine while Model 204 virtual machines are running, log onto SIRTUNED and issue any one of the following commands:

  • QUIT
  • END
  • STOP
  • SHUTDOWN

Note: When SIRTUNED terminates, data collection on all Model 204 service machines running SirTune will be immediately terminated. They will, however, continue to run Model 204 without interruption.

Every time an ONLINE running SirTune is brought up, SirTune attempts to establish an IUCV connection with SIRTUNED. If it is unable to do so, the ONLINE is not brought up. If a connection is established, SIRTUNED immediately invokes an EXEC called SIRTUNEF. This exec can then issue FILEDEFs or other commands as required.

After SIRTUNEF returns to SIRTUNED, SIRTUNED attempts to open the file that will contain the SirTune sample data. The default DDNAME used for the open is the userid of the Model 204 service machine. The actual DDNAME can be modified with a SirTune statement (SirTune configuration statements), and it is passed to SIRTUNEF.

A sample SIRTUNEF is provided on the installation tape and should be modified to suit installation requirements. SIRTUNEF is passed two parameters:

  • The userid of the Model 204 virtual machine
  • The DDNAME to be used for the open (that is, the name to be used on a FILEDEF command)

If SIRTUNEF sets a non-zero return code, SIRTUNED will return an open error to SIRTUNED and close the IUCV connection, preventing the ONLINE from coming up. After SIRTUNEF returns to SIRTUNED, SIRTUNED attempts to open the appropriate DDNAME for output. If this open fails, an open error is reflected to SirTune and the IUCV connection is closed, preventing the ONLINE from coming up.

In general, it is sufficient to allow the sample datasets to reside on a CMS format minidisk. Although data can be sent to tape, delays in manual tape handling could result in hung Model 204 virtual machines waiting for SIRTUNED to process a tape mount. Data can also be sent to OS format minidisks. To do this, however, SIRTUNED must be run under the Model 204 CMS interface (M204CMS). To do this, change the line in SIRTUNED EXEC that reads:

'SIRTUNED';

to read

'M204CMS SIRTUNED';

While it is somewhat more efficient to send sample data to an OS format minidisk than to a CMS format disk, this advantage is probably outweighed in most cases by the advantage of not having to preallocate space for each sample dataset.

The sample datasets must be variable format and should generally have a large block size (greater than 10000). If DCB information is not explicitly specified, the defaults selected by SirTune should be adequate for all but the most extreme cases. If a sample dataset fills up or a CMS minidisk becomes full, the virtual machine(s) running SirTune and associated with the full minidisk or dataset will simply stop collecting data for the duration of the run. 20 megabytes for each SirTune sample dataset should be sufficient for most shops, while 50 megabytes per dataset should be sufficient for almost any requirements.

Since the only cost of running out of space on SIRTUNED is the loss of some data, it's not worth spending a lot of time trying to size SIRTUNED exactly. Simply allocate the SIRTUNED minidisk at 20 megabytes per Model 204 virtual machine for which data is to be collected (or less if disk space is tight), and adjust the size based on experience.

For more information on sizing SIRTUNED, see SirTune size requirement for SIRTUNED. The sample SIRTUNEF EXEC on the installation tape is an example of how samples from several runs can be kept simultaneously available.

If Model 204 ONLINE service machines are brought up (AUTOLOG'ed) automatically at system initialization and some of these virtual machines will run with SirTune, the SIRTUNED service machine must complete SIRTUNED initialization before any SirTune in a Model 204 virtual machine attempts to establish an IUCV connection to SIRTUNED. Because SIRTUNED initialization is extremely quick, this can probably be guaranteed by placing an AUTOLOG command for SIRTUNED ahead of AUTOLOG commands for Model 204 service machines in the exec(s) doing the AUTOLOG'ing. To be even more certain, a CP SLEEP x SEC can be placed after the AUTOLOG of SIRTUNED to give SIRTUNED time to get through initialization, where x is some small number (1 is probably sufficient).

Using SIRTUNEA EXEC guarantees that the Model 204 service machines won't be logged on until SIRTUNED has completed initialization. SIRTUNEA EXEC is invoked by SIRTUNED after it has completed initialization. If the AUTOLOG commands for the Model 204 service machines are moved into SIRTUNEA EXEC, SIRTUNED is authorized to issue the appropriate AUTOLOGs, and an AUTOLOG command for SIRTUNED is added to the initialization exec, then SIRTUNED will automatically be logged on, and it will initialize and then bring up (AUTOLOG) the Model 204 service machines.

See also

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