# Build notes — poolside llama.cpp laguna on DGX Spark

Personal Spark build notes.

## Engine

```bash
git clone https://github.com/poolsideai/llama.cpp.git ~/src/llama.cpp-laguna
cd ~/src/llama.cpp-laguna
git checkout laguna   # pin: 04b2b72cb54048ead292884adbe11f284e3ec950
```

## Patch (measured required on this host)

`common/speculative.cpp` calls `std::isfinite`. On Spark GNU 13.3 that can fail even with `#include <cmath>` present depending on header order / libstdc++.

Measured fix that builds clean:

1. Ensure `#include <cmath>` and `#include <math.h>` near the top system includes.
2. Replace the call site:

```cpp
// before
if (!std::isfinite(v)) {

// after (Spark / GNU 13.3)
if (!::isfinite(static_cast<double>(v))) /* spark-isfinite-fix */ {
```

Do **not** treat a failed UI-asset HF fetch during build as fatal — `llama-server` still links; only the optional embedded UI may stay stale.

## Configure

```bash
export PATH=/usr/local/cuda/bin:/usr/bin:$PATH
export CUDA_HOME=/usr/local/cuda
export CC=/usr/bin/gcc CXX=/usr/bin/g++ CUDAHOSTCXX=/usr/bin/g++
# GB10: sm_121a
cmake -S . -B build \
  -DGGML_CUDA=ON \
  -DCMAKE_CUDA_ARCHITECTURES=121a \
  -DCMAKE_BUILD_TYPE=Release
cmake --build build -j"$(nproc)" --target llama-server llama-cli llama-bench
```

If CMake translates `121` poorly, force `121a`.

## Verify

```bash
export LD_LIBRARY_PATH=$HOME/src/llama.cpp-laguna/build/bin:$LD_LIBRARY_PATH
~/src/llama.cpp-laguna/build/bin/llama-server --version
# version: 1 (04b2b72)
# built with GNU 13.3.0 for Linux aarch64
```

Measured: binaries present after this patch (`llama-server`, `llama-cli`, `llama-bench`).