---
name: tilelang-build
description: Repository-specific build, rebuild, install, and test instructions for tilelang. Use when working in the tilelang repository and the correct commands are needed for building from source, reinstalling after changes, or running project tests.
---

# Build & Install

## Installing / Rebuilding tilelang

The standard way to build and install:

```bash
pip install .
```

Or with verbose output for debugging build issues:

```bash
pip install . -v
```

`uv pip install .` also works if `uv` is available but is not required.

Build dependencies are declared in `pyproject.toml` and resolved automatically during `pip install .`.

If `ccache` is available, repeated builds only recompile changed C++ files.

## Alternative: Development Build with `--no-build-isolation`

If you need faster iteration (e.g. calling `cmake` directly to recompile C++ without re-running the full pip install), install build dependencies first:

```bash
pip install -r requirements-dev.txt
pip install --no-build-isolation .
```

After this, you can invoke `cmake --build build` directly to recompile only changed C++ files. This is useful when iterating on C++ code.

## Alternative: cmake + PYTHONPATH (recommended for C++ development)

For the fastest C++ iteration, bypass pip entirely and drive cmake directly:

```bash
# Configure (auto-detects CUDA; git submodules are initialised automatically)
cmake -S . -B build

# Build
cmake --build build -j$(nproc)

# Make the local tilelang package importable
export PYTHONPATH=$(pwd):$PYTHONPATH
```

After the initial configure, recompiling is just `cmake --build build -j$(nproc)`. The runtime automatically discovers native libraries from `build/lib/` when it detects a dev checkout (see `tilelang/env.py`).

Useful cmake options:

| Flag | Purpose |
|------|---------|
| `-DUSE_CUDA=ON/OFF` | Enable/disable CUDA backend (ON by default) |
| `-DUSE_ROCM=ON` | Enable ROCm/HIP backend |
| `-DUSE_METAL=ON` | Enable Metal backend (default on macOS) |
| `-DCMAKE_BUILD_TYPE=Debug` | Debug build with `TVM_LOG_DEBUG` enabled |

## Editable Installs

**Never use `pip install -e .`** (editable install). When running Python from the repo root, the local `./tilelang` directory is imported instead of the installed copy (because `.` is on `sys.path` by default). This makes editable installs unnecessary. Avoid `pip install -e .` as it can cause import confusion with this project's layout.

## Running Tests

Most tests require a GPU.

```bash
python -m pytest testing/python/ -x
```

Run a specific test file or test case:

```bash
python -m pytest testing/python/language/test_tilelang_language_copy.py -x
python -m pytest testing/python/language/test_tilelang_language_copy.py -x -k "test_name"
```

For Metal-specific tests (requires macOS with Apple Silicon):

```bash
python -m pytest testing/python/metal/ -x
```