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koboldcpp/docs/build-profiling.md
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Daniel Bevenius 3bcfeb700f cmake : add PCH and unity build to improve build times (#28091)
* scripts : add initial profiling script (wip)

* src : add precompile headers (PCH) for models.h

* common : add common.h as PCH

* ggml : add PCH for ggml-impl.h

* mtmd : use PCH for models.h

* scripts : add script to build with Server/Tools/Tests

* server : add PCH for common.h

* docs: add profiling progress notes (wip)

* ggml : add exclude for GCC + SVE on ARM

Refs: https://github.com/ggml-org/llama.cpp/actions/runs/33393906061/job/99493756214?pr=28091

* ggml : attempt to fix use of std::hardware_destructive_inference_size

Refs: https://github.com/ggml-org/llama.cpp/actions/runs/33396221677/job/99501265689?pr=28091

* squash! ggml : attempt to fix use of std::hardware_destructive_inference_size

Add a version check for GCC 12 to conditionally apply the `-Winterference-size`
pragma.

* editorconfig : exclude profiling reports dir

This directory will not be included in the merge later and this commit
can be ignore at that point. Just fixing to keep CI happy.

* ggml : skip PCH for gcc on non-x86 architectures

* tests : add PCH for peg-parser/tests.h

There are 7 peg-parser tests that can share one PCH instead of then each
parsing the full tests.h.

* common : add PCH for chat.h

* docs : update linux build profiling full results

Just updating after a number of PCH additions. These are not exact
figures and will vary a bit from run to run, but they give a general idea
of the performance impact of PCH.

* cmake : introduce unity build for models

This commit introduces a unity build for the models to improve
compilation time.

The improvements were roughly the following:
```console
+------------------------+-----+------------+------------+------------+
| Build                  | TUs | Frontend   | Backend    | Total      |
+------------------------+-----+------------+------------+------------+
| Full,    master        | 396 |   811.0 s  |   692.2 s  | 1,503.2 s  |
| Full,    with PCH      | 405 |   380.0 s  |   664.7 s  | 1,044.7 s  |
| Full,    with PCH + UB | 264 |   357.7 s  |   635.7 s  |   993.4 s  |
+------------------------+-----+------------+------------+------------+

TU   = Translation Unit.
Full = includes Server, Tools, and Tests.
PCH  = precompiled headers.
UB   = unity build for models.
```

* docs : update linux profiling table with unitiy build results

* docs : update mac profiling results to include unity build [no ci]

* docs: remove profiling reports

* scripts : merge build profile scripts into one script

I was lazy before and just copied the first script to enable Tests,
Server, and Tools. This now merges them into a single script.

* Revert "editorconfig : exclude profiling reports dir" [no ci]

This reverts commit 2922a12118a0730d2f7632bcba265b44a0856c59.

* src : rename ggml_view_2d_slice to gemma3n_view_2d_slice

This is to be consistent with the rename in gemma4.cpp which was
required to avoid a name clash.

* cmake : add build profile script for windows [no ci]

This commit adds a port of the scripts/build-profile.sh script to
windows powershell.

This was developed on Windows on ARM but should work on X64 as well but
needs to be tested there as well.
2026-09-11 13:01:29 +02:00

123 lines
4.4 KiB
Markdown

## Build profiling
This page is a working document for analyzing the current build and try to
identify ways to improve the build time.
### Requirements
The profiling script requires clang to be used as the compiler tool chain and
also requires that ClangBuildAnalyzer is installed.
Mac:
```console
brew install clang-build-analyzer
```
Linux:
```console
git clone https://github.com/aras-p/ClangBuildAnalyzer.git
cd ClangBuildAnalyzer
cmake -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build -j$(nproc)
sudo cp build/ClangBuildAnalyzer /usr/local/bin/
```
Windows: install LLVM/clang and Ninja (e.g. via the
[LLVM releases page](https://github.com/llvm/llvm-project/releases) and
`winget install Ninja-build.Ninja`), then build ClangBuildAnalyzer the same
way as on Linux:
```console
git clone https://github.com/aras-p/ClangBuildAnalyzer.git
cd ClangBuildAnalyzer
cmake -B build -G Ninja -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_BUILD_TYPE=Release
cmake --build build --config Release
```
Then add `ClangBuildAnalyzer\build` to `PATH`.
### Usage
Mac/Linux:
```console
$ ./scripts/build-profile.sh
```
Windows:
```console
> .\scripts\build-profile.ps1
```
Both accept `--full`/`-Full` (include Server, Tools, and Tests) and a jobs
override (`-jN` / `-Jobs N`).
Note: on Windows, `cmake` defaults to the Visual Studio generator, which
ignores `CMAKE_C_COMPILER`/`CMAKE_CXX_COMPILER` and silently falls back to
MSVC. `build-profile.ps1` passes `-G Ninja` so clang is actually used, this
is required on ARM64.
### Linux (Ubuntu 24.04)
Environment:
- Clang: 18.1.3 (Ubuntu clang version 18.1.3 (1ubuntu1))
- libstdc++: GCC 13.3.0 (Ubuntu 13.3.0-6ubuntu2~24.04.1)
- Target: x86_64-pc-linux-gnu
```console
+------------------------+-----+------------+------------+------------+
| Build | TUs | Frontend | Backend | Total |
+------------------------+-----+------------+------------+------------+
| Minimal, master | 249 | 468.2 s | 270.3 s | 738.5 s |
| Minimal, with PCH | 253 | 177.1 s | 265.8 s | 442.9 s |
| Full, master | 396 | 811.0 s | 692.2 s | 1,503.2 s |
| Full, with PCH | 405 | 380.0 s | 664.7 s | 1,044.7 s |
| Full, with PCH + UB | 264 | 357.7 s | 635.7 s | 993.4 s |
+------------------------+-----+------------+------------+------------+
PCH = precompiled header.
Full = includes building Server, Tools, and Tests.
UB = unity build for models
```
Note that the number of translation units (TUs) increases when using precompiled
headers — each PCH target adds one extra TU for the precompilation step itself.
### Mac (Apple M3)
Environment:
- Clang: Apple clang version 17.0.0 (clang-1700.3.19.1)
- libc++: ships with Apple clang 17.0.0 (Xcode toolchain)
- Target: arm64-apple-macosx15.6
```console
+------------------------+-----+------------+------------+------------+
| Build | TUs | Frontend | Backend | Total |
+------------------------+-----+------------+------------+------------+
| Minimal, master | 256 | 154.5 s | 94.8 s | 249.3 s |
| Minimal, with PCH | 261 | 65.9 s | 90.0 s | 155.9 s |
| Full, master | 407 | 265.7 s | 209.7 s | 475.4 s |
| Full, with PCH | 414 | 154.6 s | 197.5 s | 352.1 s |
| Full, with PCH + UB | 274 | 143.0 s | 192.2 s | 335.2 s |
+------------------------+-----+------------+------------+------------+
PCH = precompiled header.
Full = includes building Server, Tools, and Tests.
UB = unity build for models
```
### Windows (ARM64)
Environment:
- Clang: clang version 22.1.8 (LLVM, `C:\Program Files\LLVM`)
- STL: MSVC STL (Visual Studio 2022 Build Tools 14.44.35207)
- Target: aarch64-pc-windows-msvc
```console
+------------------------+-----+------------+------------+------------+
| Build | TUs | Frontend | Backend | Total |
+------------------------+-----+------------+------------+------------+
| Minimal, master | 249 | 159.4 s | 82.2 s | 241.6 s |
| Full, master | 373 | 337.2 s | 167.4 s | 504.6 s |
| Minimal, with PCH + UB | 113 | 62.3 s | 82.4 s | 144.7 s |
| Full, with PCH + UB | 240 | 233.0 s | 185.1 s | 418.1 s |
+------------------------+-----+------------+------------+------------+
PCH = precompiled header.
Full = includes building Server, Tools, and Tests.
UB = unity build for models
```