Profiling and Performance Tools

To generate profiling information, you use the compiler, linker, and the profiler from either the visual development environment or the command line.

Select those parts of your application that make the most sense to profile. For example, routines that perform user interaction may not be worth profiling. Consider profiling routines that perform a series of complex calculations or call multiple user-written subprograms.

Profiling identifies areas of code where significant program execution time is spent. It can also show areas of code that are not executed. Visual Fortran programs created in a Windows ia32 development environment can be run and analyzed on a Windows NT 4, Windows 2000, Windows 98, Windows Me, or Windows 95 system. Whenever possible, perform detailed performance analysis on a system that closely resembles the system(s) that will be used to run the actual application.

For detailed information about profiling from the command line, see Profiling Code from the Command Line.

There are two main types of profiling: function profiling and line profiling.

Function Profiling

Function profiling helps you locate areas of inefficient code. It can show:

• The time spent in functions and the number of times a function was called (function timing).
• Only the number of times a function was called (function counting).
• A list of functions executed or not executed (function coverage).
• Information about the stack when each function is called (function attribution).

Function profiling does not require debug information (it obtains addresses from a .MAP file). Since function profiling (except function attribution) uses the stack, routines that modify the stack cannot be profiled. Exclude object files for routines that modify the stack.

To perform function profiling:

1. In the Project menu, select Settings.
2. Click the Link tab.
3. In the General category, click the Enable profiling checkbox (this turns off incremental linking).
4. In the General category, click the Generate mapfile checkbox.
5. Click OK to accept the current project settings.
6. Build your application.
7. After building your application, profile your project.

Line Profiling

Line profiling collects more information than function profiling. It shows how many times a line is executed and whether certain lines are not executed. Line profiling requires debug information.

To perform line profiling:

1. In the Project menu, select Settings.
2. Click the Link tab.
3. In the General category, click the Enable profiling checkbox (this turns off incremental linking).
4. In the General category, click the Generate debug information checkbox.
5. Click on the Fortran tab.
6. In the category drop-down list, select Debug.
7. In the Debugging level drop-down list, select Full.
8. In the Debugging level drop-down list, click the Use Program Database for Debug Information checkbox.
9. Click OK to accept the current project settings.
10. Build your application
11. After building your application, profile your project.

Performance Tools

Tools that you can use to analyze performance include:

• Process Viewer (Pview) lets you view process and thread characteristics.
• Spy++ provides a graphical view of system use.
• On Windows NT or Windows 2000 systems, the Windows Performance Monitor can help identify performance bottlenecks.
• Other performance tools are available in the Microsoft Win32 SDK (see the online Platform SDK Tools Guide, Tuning section in HTML Help Viewer).

You can also purchase separate products to perform performance analysis and profiling.

Efficient Source Code

Once you have determined those sections of code where most of the program execution time is spent, examine these sections for coding efficiency. Suggested guidelines for improving source code efficiency are provided in the following sections:

• Data Alignment Considerations
• Use Arrays Efficiently
• Improve Overall I/O Performance
• Additional Source Code Guidelines for Run-Time Efficiency

For information about timing your application and for an example command procedure that uses the Windows NT Performance Monitor, see Timing Your Application.