Displaying VMC Statistics in the Workload Monitor

Context

The Business Transaction Analysis (transaction STAD) is used to display and evaluate kernel statistical data for user transactions or background processing as well as for evaluating application-specific statistical data.

A transaction within a user session can be carried out in several dialog steps. At the end of each dialog step the SAP kernel writes a statistic record with its associated subrecords to the buffer. This information is then passed through an explicit buffer flush to the file either automatically once an hour, or as and when required.

If the VM Container has been used in a dialog step, this is indicated by the entry in column, VMC Elapsed Time (ms).

Procedure

Call transaction STAD. The initial screen SAP Workload: Business Transaction Analysis appears with the following selection options.
Restrict the hit list with your search criteria so that you do not get too many irrelevant statistic records. In particular, use the Server Selection if you are interested in records only from this application server. By default all records are selected.

Caution
Note that when you are selecting the time interval, statistic records are written from the kernel at the end of each dialog step. The data is therefore sorted chronologically by the end time of each statistic record. If you want to find a given statistic record, the read interval needs to be aligned to the end time of the transaction step.

A list of statistic records is displayed. You can recognize VMC records from the entry in VMC elapsed time (ms) which will not be zero.
To select the VMC statistic record you want, double-click it. A detailed view of this record appears ( SAP Workload: Single Statistic Records - Details). In the menu bar choose VMC, or scroll right to the bottom. Here you will find the VMC data.

Results

You can see the VMC statistics for this dialog step.

To display the details for an area choose the magnifying glass ( ).

Activity/Task (Value)	Explanation	More information:
`VMC CPU time`	CPU time needed by the VMC
`Container framework`	CPU time needed by the VMC framework	Container Framework
`VM elapsed time`	Total time used by the VMs...	See below
	`Code generation`	... for generating code
`Garbage Collection`	... for the garbage collection
`other time`	.. otherwise
`Class loading`	Memory allocated and freed for the representation of Java classes	Class Loading
`Code generation`	Memory allocated and freed for generating code (Java source code, Java byte code, native code)	Code Generation
`I/O transferred`	Total amount of bytes transferred	I/O Overview
`Number of VMC calls`	Number of calls to the VMC
`Java Memory Management - GC`	Garbage collection details	How the Local Garbage Collector Works
	`count local`	Number of local garbage collections (local = young generation + old generation)
`count shared`	Number of shared garbage collections (garbage collection of the shared memory)
`CPU time`	CPU time needed for the garbage collections
`Java Memory Management - Java Heap`	Details of the Java heap management
	`allocated local`	Total number of allocations in the Java heap
`allocated shared`	Total number of allocations in the shared pool
`freed local`	Memory released in the local heap by the garbage collector
`freed shared`	Freed up memory in the shared memory
`promoted`	Memory promoted by the garbage collector (from the young generation into the old generation)
`Miscellaneous`	Not yet used in this release