About Code Profiling

A profiler is a program that provides information on the execution of a program. Usually the information provided is on execution times, but there are profilers that also record other data such as memory usage. Some profilers just record the count and time spent in each procedure of a program.

How They Work

Profilers can gather their data in many ways. Some profilers get their data through operating system's "hooks" that provide profiling data.

Others add instrumentation code to the program to collect data.

If the operating system doesn't provide "hooks" for getting the data, and modifying the existing code is not a good option, a profiler can get its data by sampling the "state" of a running program. The "state" of the program is recorded as a mini-dump of the program containing information on the currently running code.

For more information on profilers, see the Wikipedia article on Profiling (computer programming).

Profiler

ProfileThe Application Profiler is a performance analysis tool that can determine where the elapsed time is spent for a program running on a ClearPath system.  The tool can collect this information without any changes to the program. The Application Profiler is able to determine which statements and procedures are used most heavily including any activities that occur in libraries, DMSII, COMS or the MCP.

Architecture

The Application Profiler package consists of four main components.

  • A sampler program that collects data about a program running on the system.
  • An analyzer program that post-processes the data from the sampler program to create data files for further analysis on a PC.
  • Three Microsoft Access databases that hold data from one or more sampling sessions.
  • A Windows-based browser program that is used to view the analyzed data.

Profiling a Program

To profile a program, you run the sampler program on the ClearPath system, giving the mix number of the program to be sampled. Next you run the analyzer program on the same system you ran the sampler. The analyzer locates the code files used by the program to determine procedure names and sequence numbers for its analysis. The results of the analysis are stored in files that can be loaded by the Windows browser program.

On a PC, the browser program is run to import the ClearPath data into the Access databases. Finally, the browser program is used to do queries against the databases to show the results of the analysis.

Displaying the Results

You can see where the program is spending its time in many different ways. You can look at the sampling statistics in the following ways:

  • Profiler screen shotActive address
  • Active code files
  • Active sequence numbers
  • Active sequence numbers when not waiting
  • Target program sequence numbers
  • Top user sequence number
  • Top user code files
  • Top user address
  • Counts by wait time