Fortran Profile-guided Optimization (PGO) Sample

This sample demonstrates the use of the Profile-Guided Optimization (PGO) feature of the Intel compilers. For details on the PGO feature, please refer to the compiler documentation.

Using PGO is a multistep process:

Compile the application with /Qprof-gen (Windows*) or -prof-gen (Linux* and macOS*) specified. This creates an instrumented executable.
Run the application using a reduced-size dataset that is representative of the actual workload. Each run will create a .dyn file with profile information.
Compile the application with /Qprof-use (Windows) or -prof-use (Linux* and macOS*) specified. This will create an optimized executable.

Note: the following options are used for reporting purpose

/Qopt-report:1 (Windows) or -qopt-report=1 which tells the compiler to generate an optimization report with the lowest level of detail.
/Qopt-report-phase:pgo (Windows) or -qopt-report-phase=pgo (Linux* and macOS*) which specifies that the optimization report is to be generated for the Profile Guided Optimization phase.

System Requirements:

Hardware:
- Any Intel® processor like 2nd Generation Intel® Core™ i3, i5, or i7 processors and Intel® Xeon® E3 or E5 processor family
For Microsoft* Windows*:
- Microsoft Visual Studio 2013*, 2015* or 2017* Professional Edition or above
- Intel® Parallel Studio XE 2019 Composer Edition for Fortran Windows* or newer
For Linux*:
- GNU* GCC 4.5 or newer
- Intel® Parallel Studio XE 2019 Composer Edition for Fortran Linux* or newer
For macOS*:
- macOS* 10.12 or above
- Xcode* 8 or above
- Intel® Parallel Studio XE 2019 Composer Edition for Fortran macOS* or newer

Build Instructions

For Visual Studio users:

Open the solution .sln file
Clean the solution (Build > Clean Solution)
Select the "prof_gen" configuration from the toolbar
Build the project
Run the application (Ctrl-F5)
Select the "prof_use" configuration.
Build the project and examine the build output.

For Windows Command Line users:

Open the appropriate Intel Fortran compiler command prompt and navigate to sample folder
Compile: ifort /Qprof-gen src\pgo_sample.f90
Run the program: pgo_sample.exe
Recompile: ifort /Qprof-use /Qopt-report:1 /Qopt-report-phase:pgo src\pgo_sample.f90

For Linux*/macOS* users:

Set the ifort environment: source <ifort-install-dir>/bin/compilervars.sh {ia32|intel64}
Navigate to sample directory
Compile: ifort -prof-gen src/pgo_sample.f90
Run the program: pgo_sample.exe
Recompile: ifort -prof-use -qopt-report=1 -qopt-report-phase=pgo src/pgo_sample.f90

Note:that the when the build is done with /Qprof-use or -prof-use, the compiler will comment that _ADDERMOD has no .DYN information. This is because _ADDERMOD is a null routine generated for the module and it is never called.