Basic Profile-Guided Optimization Options

In cases where your code behavior differs greatly between executions, you have to ensure that the benefit of the profile information is worth the effort required to maintain up-to-date profiles. In the basic profile-guided optimization, the following options are used: -prof_gen and -prof_use.

Option

Description

-prof_gen

Instructs the compiler to produce instrumented code in your object files in preparation for instrumented execution.

Note
The dynamic information files are produced in phase 2 when you run the executable.

-prof_use

Instructs the compiler to produce a profile-optimized executable and merges available dynamic information (.dyn) files into a pgopti.dpi file. If you perform multiple executions of the instrumented program, -prof_use merges the dynamic information files again and overwrites the previous pgopti.dpi file.

Note
For Itanium™-based applications, if you intend to use the -prof_use option with optimizations at the -O3 level, the -O3 option must be on. If you intend to use the -prof_use option with optimizations at the -O2 level or lower, you can generate the profile data with the default options.