Move AutoFDO-specific instructions to separate file

1 files changed, 0 insertions, 145 deletions

diff --git a/BUILD.md b/BUILD.md
index 2a8b6cf40..3e148e040 100644
--- a/BUILD.md
+++ b/BUILD.md
@@ -18,12 +18,7 @@ notes below.
   - [Additional Tips](#additional-tips)
     - [Compiler variations](#compiler-variations)
     - [Build Results, Rebuilding, and Cleaning](#build-results-rebuilding-and-cleaning)
-    - [CCache](#ccache)
     - [Optimization Modifiers](#optimization-modifiers)
-  - [AutoFDO Procedures](#autofdo-procedures)
-    - [Prerequisites for AutoFDO](#prerequisites-for-autofdo)
-    - [Record Data for AutoFDO Builds](#record-data-for-autofdo-builds)
-    - [Build Using AutoFDO Data](#build-using-autofdo-data)
 
 ## Linux Procedures
 
@@ -67,146 +62,6 @@ common options to the **list-build-dependencies.sh** and **build.sh** scripts:
   compiler (if available in your package manager)
 - `--bit-depth 32`, to build a 32-bit binary instead of 64-bit
 
-### Optimization Modifiers
-
-The following modifier flags can be added when building a **release** type:
-
-- `-m lto`, optimize the entire object space instead of per-file (Only
-  available on Mac and Linux)
-
-- `-m fdo`, performs feedback directed optimizations (FDO) using an AutoFDO
-  data set. Export the `FDO_FILE` variable with the full path to your merged
-  FDO dataset. For example:
-
-  - GCC: `export FDO_FILE=/full/path/to/current.afdo` and then build with:
-
-    `./scripts/builds.sh -c gcc -t release -m fdo -m lto`
-
-  - Clang: `export FDO_FILE=/full/path/to/current.profraw`, and then build
-    with:
-
-    `./scripts/builds.sh -c clang -t release -m fdo -m lto`
-
-  The section below describes how to collect an AutoFDO dataset for GCC and
-  Clang.
-
-## AutoFDO Procedures
-
-Feedback Directed Optimization (FDO) involves recording performance data from
-the Linux kernel and using it to direct the compiler's optimizer.
-
-### Prerequisites for AutoFDO
-
-- An **Intel processor** that supports the last branch record (LBR) instruction.
-- A Linux **kernel** built with Branch Profiling tracers enabled:
-
-  ``` shell
-  CONFIG_PM_TRACE=y
-  CONFIG_TRACE_BRANCH_PROFILING=y
-  CONFIG_BRANCH_TRACER=y
-  ```
-
-  These can be enable directly in your kernel's `.config` file or using `make
-  menuconfig` via the following menu options:
-  1. `Kernel hacking  --->`
-  1. `[*] Tracers  --->`
-  1. `Branch Profiling (Trace likely/unlikely profiler)`
-  1. `(X) Trace likely/unlikely profiler`
-
-- The **AutoFDO** software package. It may be available via your package
-  manager or built from sources <https://github.com/google/autofdo>.
-
-  - **Note about compiler versions** the autofdo binaries need to be compiled
-    with the exact version of the compiler that will later be used to compile
-    our final optimized version of dosbox-staging.
-
-    So for example, if you install autofdo via package-manager, then it will be
-    valid for the default version of gcc and clang also installed by your
-    package manager.  Where as if you plan to build with  `gcc-<latest>`, then
-    you will need to compile autofdo from sources using `gcc-<latest>` by
-    pointing the `CC` and `CXX` environment variables to the newer gcc
-    binaries.
-
-  - **Note about clang** If you plan to compile with a version of clang newer
-    than your package manager's default version, then you will need to compile
-    autofdo from source and configure it with the corresponding version of
-    `llvm-config`.  For example, if I want to build with clang-10, then I would
-    configure autofdo with: `./configure --with-llvm=/usr/bin/llvm-config-10`.
-
-  - The included `.github/scripts/build-autofdo.sh` script can be used to build
-    and install autofdo, for example:
-
-    - default GCC:
-
-      `sudo .github/scripts/build-autofdo.sh`
-    - newer GCC:
-
-      ``` shell
-      export CC=/usr/bin/gcc-9
-      export CXX=/usr/bin/g++-9
-      sudo .github/scripts/build-autofdo.sh
-      ```
-
-    - Clang version 10:
-
-      `sudo .github/scripts/build-autofdo.sh`
-
-- The **pmu-tools** software package, which can be downloaded from
-  <https://github.com/andikleen/pmu-tools.> This is a collection of python
-  scripts used to assist in capturing sampling data.
-
-### Record Data for AutoFDO Builds
-
-1. Ensure the custom Linux Kernel supporting LBR tracing is running.
-
-2. Build `dosbox-staging` from source using the `fdotrain` target:
-   `./scripts/build.h -c gcc -t fdotrain`
-
-3. Record kernel sample profiles while running dosbox-staging:
-
-    `/path/to/pmu-tools/ocperf.py record -F max -o "samples-1.prof" -b -e
-    br_inst_retired.near_taken:pp -- /path/to/fdo-trained/dosbox ARGS`
-
-   Where `samples-1.prof` is the file that will be filled with samples.
-
-   Repeat this for multiple training runs, each time saving the output to a new
-   `-o samples-N.prof` file.  Ideally you want to exercise all code paths in
-   dosbox-staging (core types, video cards, video modes, sound cards, and audio
-   codecs).
-
-4. Convert your sample profiles into compiler-specific records using tools
-   provided in the `autofdo` package:
-
-   For GCC, run:
-   - `create_gcov --binary=/path/to/fdo-trained/dosbox
-     --profile=samples-1.prof -gcov=samples-1.afdo -gcov_version=1`
-
-     ... for each `.prof` file, creating a corresponding `.afdo` file.
-
-   - At this point, you now have an `.afdo` file for each `.prof` file. Merge
-     the `.afdo`s into a single `curren.afdo` file with:
-
-     `profile_merger -gcov_version=1 -output_file=current.afdo *.afdo`
-
-   For Clang, run:
-
-   - `create_llvm_prof --binary=/path/to/fdo-trained/dosbox
-     --profile=samples-1.prof --out=samples-1.profraw`
-
-     ... for each `*.prof` file, creating a corresponding `.profraw` file.
-
-   - At this point, you now have a `.profraw` file for each `.prof` file. Merge
-     them into a single `current.profraw` file with:
-
-     `llvm-profdata-<version> merge -sample -output=current.profraw *.profraw`
-
-### Build Using AutoFDO Data
-
-You can now use your merged `.afdo` or `.profraw` file to build with the `-m
-fdo` modifier by  placing your `current.afdo/.profraw` file in the repo's root
-directory, or point to it using the FDO_FILE environment variable, and launch
-the build with `./scripts/build.sh -c <gcc or clang> -t release -m lto -m fdo`.
-
 ## Meson build snippets
 
 ### Make a debug build