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Program Profiling Print E-mail
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Written by Chamara Withanachchi   

Profiling is to find the hot spots in your program–the most frequently executed procedures, and paths through those procedures.


Profiling Overview

At a high level, profiling consists of three phases:


* Instrumentation
* Data gathering
* Optimization


It’s important to note profiling improves the performance of your application level code. It doesn’t improve other aspects of the system that affect performance. For example, if your application spends 90 percent of its time in system calls to access the database, profiling can only improve the performance of the other 10 percent. In such an application, the benefit from profiling may be minimal. If, however, your ILE application spends at least 25 percent of its time in the application code, then you may see a noticeable improvement from profiling.


Programs and service programs consisting of many procedures with frequent procedure calls will generally see more improvement from profiling than those having only a few procedures. This is because profiling is used to improve automatic inlining of one procedure into another, and the optimization to package hot procedures together is more effective when there are many procedures. However, programs with only a few procedures can still see significant benefit from profiling.


Since profiling takes some additional effort, it should be done late in your application development cycle so it isn’t done repeatedly. Typically your application should be complete and well-tested before applying profiling to improve performance.


Based on Dawn May's Article

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