Profile Guided Optimization - ProkopHapala/FireCore GitHub Wiki

To perform Profile-Guided Optimization (PGO) with CMake and g++, you'll need to follow a few steps:

1. Compile Your Code with Instrumentation: First, you need to compile your code with compiler instrumentation enabled. This generates profiling data when you run your program.

2. Run Your Program to Collect Profiling Data: Execute your program on representative input data to collect profiling information. This data will be used by the compiler to guide optimizations.

3. Recompile Your Code with PGO: Re-compile your code using the profiling data collected in the previous step to guide optimizations.

Here's how you can accomplish this with CMake and g++:

1. Modify your CMakeLists.txt file to include PGO flags:

# Enable compiler optimizations and profiling
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O2 -fprofile-generate")

# Add your executable
add_executable(your_executable_name your_source_files.cpp)

2. Build your project:

mkdir build
cd build
cmake ..
make

3. Run your program with representative input to generate profiling data.

4. Re-compile your code using the collected profiling data:

# Modify CMakeLists.txt to re-compile with PGO
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O2 -fprofile-use")

# Rebuild your project
cmake ..
make

This setup will compile your code with instrumentation for profiling data collection (-fprofile-generate), then after running the program with representative input, it will re-compile your code using the collected profiling data (-fprofile-use). This second compilation pass optimizes your code based on the collected profiling information.

Remember to replace your_executable_name with the name of your actual executable and your_source_files.cpp with your actual source files.

With these steps, you can utilize Profile-Guided Optimization with CMake and g++ to improve the performance of your C++ code.