Developer Guide and Reference

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Profile-Guided Optimization Report

The PGO report can help identify where and how the compiler used profile information to optimize the source code. The PGO report can also identify where profile information was discarded due to source code changes made between the time of instrumentation and feedback steps. The PGO report is most useful when combined with the PGO compilation steps outlined in the topic, Profile an Application with Instrumentation. Without the profiling data generated during the application profiling process the report will generally not provide useful information.
Combine the final PGO step with the reporting options by including
-prof-use
(Linux* and
macOS*
) or
/Qprof-use
(Windows*).
The following syntax examples demonstrate how to run the report using the combined options.
Operating System
Syntax Examples
Linux*
icpc -prof-use -qopt-report-phase=pgo pgotools_sample.c
macOS*
icpc -prof-use -qopt-report-phase=pgo pgotools_sample.c
Windows*
icl /Qprof-use /Qopt-report-phase:pgo pgotools_sample.c
By default the PGO report generates a medium level of detail (where the
[q or Q]opt-report
argument
n
=2). You can use the
-qopt-report=
n
(Linux and
macOS*
) or
/Qopt-report:
n
option
along with the
[q or Q]opt-report-phase
option if you want a greater or lesser level of diagnostic detail
.
The output, by default, comes out to a file with the same name as the object file but with an
.optrpt
extension and is written into the same directory as the object file. Using the entries in the example above, the output file will be
pgotools_sample.optrpt
.
Use the
-qopt-report-file
(Linux and
macOS*
) or the
/Qopt-report-fil