Monitoring Performance Using CP Monitor

The CP Monitor facility collects system performance data. This data can be processed by an external data reduction program to produce statistics to give you an understanding of system operation or help you analyze the use of, and contention for, major system resources. These resources include processors, storage, I/O devices, and the paging subsystem. You can control the amount and nature of the data collected. In general, monitoring is in this order:

  1. You use the CP privileged command, MONITOR, to control monitoring, including the type, amount, and nature of data to be collected.
  2. An application program running in a CMS virtual machine connects to the CP *MONITOR System Service to establish a data link with CP.
  3. The monitor collects performance data during CP operation and stores it, in the form of monitor records, in a saved segment.
  4. The application program retrieves monitor records from the saved segment and processes them.

An IBM®-supplied program, called MONWRITE, can be used as the application program to establish communication links with CP and retrieve monitor records. MONWRITE not only retrieves monitor records from the saved segment but also stores them on tape or in a CMS file on disk. An application program can then later read the records from the file and perform data reduction on the performance data found in the records.

The performance monitor in the optional Performance Toolkit for z/VM® feature collects data from CP control blocks in real storage and also from CP MONITOR records. The Performance Toolkit for z/VM can also display performance data from MONWRITE files on disk or tape. For more information, see z/VM: Performance Toolkit Reference.

The z/VM Performance Data Pump (Data Pump) is delivered as an enhancement of the charged Performance Toolkit for z/VM component. Data Pump converts (machine readable) z/VM monitor and SFS data into a generic text-based data stream. Data Pump can also read MONWRITE files. Modern tools can use the data stream to display real-time performance dashboards, aggregate real-time data for long-term usage analysis, or integrate with existing enterprise observability solutions. For more information, see z/VM Performance Data Pump.