Activities
You can perform the following activities in VMC profiling.
Start and Close a Session
Once the analysis parameters have been activated, you can start the profiling. As soon as profiling has started, the requested data in the VMs is collected and stored as compressed raw data in the file system. In the session overview the new session appears with the status "Not Closed".
You can select and close the session in the overview screen at any time.
Evaluate session
You can evaluate the closed profiling sessions and display the results of the analysis at any time.
For the evaluation of the individual analyses, the data belonging to the analysis is extracted from the compressed profiling raw data and formatted for the relevant display. The analysis includes determining frequencies, calculating totals and statistical values, and sorting the data. The evaluation is performed in one of the VMs in the VM Container when you select an individual analysis for display (see restrictions).
Once the raw data has been evaluated, it is passed to the profiling transaction and displayed. Whether the data is displayed as a table, tree, graphic or as separate values depends on the type of data.
Delete session
You can delete individual profiling sessions from the session overview at any time. The raw data and any saved evaluation data is deleted in the file system (see restrictions).
A session can only be deleted if the profiling data is stored in directory DIR_DATA (or in a subdirectory of this).
This is the default value for system parameter vmcj/prof/directory.
Restrictions
Start Session
Although it is technically possible to start multiple profiling sessions at the same time (for instance, for different users), you should be aware that the different session results could affect one other due to the system overhead required for collecting the analysis data. This is especially the case with method sampling, since sampling time points are implemented by internal VM timers that are resource-intensive.
Evaluate Analyses
With the majority of analyses the first evaluation takes significantly longer than subsequent ones, because the necessary calculations are performed only for the first evaluation, and then they are stored in internal format in the file system. Subsequent evaluations can then be relatively quickly reconstructed, and if required, filtered and sorted.
For profiling in longer-running applications we recommend you do not run resource-intensive analyses, such as the reference analysis or the method trace, together with other analyses within the same session. If you do, the time limit for an ABAP program may expire already in the first evaluation.
Delete session
Since the volume of profiling raw data and internal data from the first evaluation can be very large, the file system may run out of space. We recommend therefore that you delete profiling sessions that are no longer needed.
The VMC profiling data is deleted automatically after 30 days. The default value for this "expiry age" can be changed with system profile parameter vmcj/prof/maxAge.
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