[ Previous | Next | Contents | Glossary | Home | Search ]
AIX Versions 3.2 and 4 Performance Tuning Guide

Restructuring Executables with fdpr

The fdpr (feedback-directed program restructuring) program optimizes executable modules for faster execution and more efficient use of real memory. It is available on AIX Version 4 systems as part of the Performance Toolbox for AIX. To determine whether fdpr is available on your system, use:

lslpp -lI perfagent.tools

If this package has been installed, fdpr is available.

fdpr processing takes place in three stages:

As an example, the command:

fdpr -p ProgramName -R3 -x test.sh

would use the testcase test.sh to run an instrumented form of program ProgramName . The output of that run would be used to perform the most aggressive optimization (R3) of the program to form a new module called, by default, ProgramName.fdpr . The degree to which the optimized executable performed better in production than its unoptimized predecessor would depend largely on the degree to which test.sh successfully imitated the production workload.

Attention: The fdpr program incorporates advanced optimization algorithms that sometimes result in optimized executables that do not function in the same way as the original executable module. It is absolutely essential that any optimized executable be exhaustively tested before being used in any production situation; that is, before its output is trusted.

In summary, users of fdpr should:

[ Previous | Next | Contents | Glossary | Home | Search ]