Getting the data you want

However, a few of the 79 subtypes require additional support before they can be displayed online or written to a data set. This section describes these requirements. (For more information about CMF Type 79 API, see CMF Type 79 API.)

CMF Type 79 API

This topic describes CMF Type 79 API.

The CMF Type 79 application program interface (API) provides an interface to SMF type 79 records for use by CMFMON and other performance tools.

For example, SDSF 1.3.3 displays certain fields from SMF records 79-1 and 79-2 using the CMF Type 79 API. In addition, performance monitors, such as the IBM OMEGAMON product, have also adopted the CMF Type 79 API to display data concerning device utilization, page/swap data set activity, and channel path utilization.

For details about the CMF APIs, see Developing.

CMF Extractor requirements

Some 79 record subtypes require an active Extractor sampler to provide the data.

If you are planning to display any of the screens or code any of the control statements that are shown in the first column of the following table, make sure the corresponding sampler is active in CPM mode :

Data returned by these subtypes reflects activity that occurred during the current CMF recording interval. These fields are reset at the beginning of each interval.

BBXS requirements

When certain fields in subtype 2 and 3 are requested, the BBX subsystem (BBXS) must also be active. In addition, record subtype 12 requires channel measurement, which typically is provided by BBXS.

If BBXS is not active when subtype 2 records are requested, the fields shown in the following table contain null data. The equivalent fields in the CMFMON online component appear on the ARD screen; these fields are identified in the following table.

Fields containing null data when BBXS is inactive

 Flag R792RSM is set to indicate that these fields are invalid.

If BBXS is not active when subtype 3 records are requested, the record cannot be returned at all. The CMF Type 79 API issues a return code of 12 to indicate that an external sampler is required.

XDS requirements

Displaying data from a remote system or displaying 79 subtype 15 records requires XDS to provide the data.

If you are planning to display remote system data or display the ILOCK screen, make sure the XDS data buffer is active. For more information, see Displaying-data-from-a-remote-system.

Additional ILOCK screen requirements

CMFMON displays ILOCK data from all systems. Therefore, XDS must be active on every system from which you want information, as well as on the local system.

The ILOCK screen has no data-gathering component. Instead, the retrieval of the IRLM data from the SMF data buffer is done by CMFMON.

Data collection is initiated by the operator who, at the console, issues the RUNTIMEO exit for one system in the sysplex by typing

F irlmid,RUNTIMEO

The command will be propagated automatically to all other systems.

When the SMF records are eventually written by the IRLMs in the data-sharing group, the reporter can fetch these SMF records (79-15) out of the XDS data buffer.

If you request ILOCK information and receive the message that no data is available for the report, you need to ask the operator to issue the previously discussed command.

Other requirements

If you are running in a PR/SM or MDF environment, the Extractor CPU sampler must be active for the CMF Type 79 API to report on system CPU utilization. If the CPU sampler is not active in a PR/SM environment, the API returns a value of -1 (x'FFFFFFFF') in field R793CPUU instead of CPU utilization data.