Tech review of PGO in Windows

Author: jasonrandrews

content/learning-paths/laptops-and-desktops/win_profile_guided_optimisation/_index.md

@@ -16,7 +16,7 @@ learning_objectives:
 
 prerequisites:
     - Basic C++ understanding.
-    - A Windows on Arm machine with [Visual Studio 2022](/install-guides/vs-woa/) and the C++ desktop development workload installed.
+    - A Windows on Arm machine with [Visual Studio](/install-guides/vs-woa/) and the C++ desktop development tools installed.
 
 author: Tom Dunkle
 

content/learning-paths/laptops-and-desktops/win_profile_guided_optimisation/how-to-2.md

@@ -10,7 +10,7 @@ Before you start working with Profile-Guided Optimization, you need to understan
 
 Google Benchmark is a C++ library specifically designed for microbenchmarking, which means measuring the performance of small code snippets with high accuracy. Microbenchmarking helps you identify bottlenecks and optimize critical sections, especially in performance-sensitive applications. 
 
-Google Benchmark simplifies this process by providing a framework that manages iterations, times execution, and performs statistical analysis. This lets you focus on the code being measured, rather than writing boilerplate or trying to prevent unwanted compiler optimizations manually.
+Google Benchmark simplifies this process by providing a framework that manages iterations, times execution, and performs statistical analysis. This lets you focus on the code being measured, rather than writing test code or trying to prevent unwanted compiler optimizations manually.
 
 To use Google Benchmark, you define a function that accepts a `benchmark::State&` parameter and iterate over it to perform the benchmarking. You register the function using the `BENCHMARK` macro and include `BENCHMARK_MAIN()` to generate the benchmark's entry point.
 

content/learning-paths/laptops-and-desktops/win_profile_guided_optimisation/how-to-3.md

@@ -14,14 +14,18 @@ For this example, you'll use an Arm computer running Windows.
 
 ## Install the required tools
 
-First, you need to install Google Benchmark for Arm64 via vcpkg. Run the following commands in PowerShell as Administrator:
+### Install vcpkg and Google Benchmark
+
+Run the following commands in PowerShell:
 
 ```console
-cd C:\git
-git clone https://github.com/microsoft/vcpkg.git
-cd vcpkg
-.\bootstrap-vcpkg.bat
-.\vcpkg install benchmark:arm64-windows-static
+iex (iwr -useb https://aka.ms/vcpkg-init.ps1)
+cd $HOME
+mkdir pgo-benchmark
+cd pgo-benchmark
+& "$HOME\.vcpkg\vcpkg.exe" new --application
+& "$HOME\.vcpkg\vcpkg.exe" add port benchmark
+& "$HOME\.vcpkg\vcpkg.exe" install
 ```
 
 ## Create the division benchmark
@@ -52,21 +56,24 @@ BENCHMARK_MAIN();
 
 ## Compile and run the baseline benchmark
 
+Open an **ARM64 Native Tools Command Prompt** from the Start menu, then type `powershell` to start PowerShell with the ARM64 compiler environment.
+
 Before compiling, set an environment variable to refer to the vcpkg installation directory:
 
 ```console
-$VCPKG="C:\git\vcpkg\installed\arm64-windows-static"
+$VCPKG="$HOME\pgo-benchmark\vcpkg_installed\arm64-windows"
 ```
 
 Now compile the benchmark. This command uses the MSVC compiler and links with the Google Benchmark libraries:
 
 ```console
-cl /D BENCHMARK_STATIC_DEFINE div_bench.cpp /link /LIBPATH:"$VCPKG\lib" benchmark.lib benchmark_main.lib shlwapi.lib
+cl /I"$VCPKG\include" /D BENCHMARK_STATIC_DEFINE div_bench.cpp /link /LIBPATH:"$VCPKG\lib" benchmark.lib benchmark_main.lib shlwapi.lib
 ```
 
 Run the program to establish your baseline performance:
 
 ```console
+$env:PATH += ";$HOME\pgo-benchmark\vcpkg_installed\arm64-windows\bin"
 .\div_bench.exe
 ```
 

content/learning-paths/laptops-and-desktops/win_profile_guided_optimisation/how-to-4.md

@@ -10,18 +10,12 @@ Now that you have a baseline benchmark, you're ready to apply Profile-Guided Opt
 
 ## Build the instrumented binary
 
-First, open the Arm developer shell so the compiler is in your PATH:
-
-```console
-& "C:\Program Files\Microsoft Visual Studio\18\Community\Common7\Tools\Launch-VsDevShell.ps1" -Arch arm64
-```
-
-You may need to change the version number in your Visual Studio path, depending on which version you've installed.
+You should already have an ARM64 Native Tools Command Prompt open with PowerShell running from the previous section.
 
 Set the environment variable to refer to the vcpkg installation directory:
 
 ```console
-$VCPKG="C:\git\vcpkg\installed\arm64-windows-static"
+$VCPKG="$HOME\pgo-benchmark\vcpkg_installed\arm64-windows"
 ```
 
 Build the instrumented binary with the `/GENPROFILE` flag. This creates a version of your program that records how it executes: