Summary:
Pull Request resolved: https://github.com/facebookresearch/faiss/pull/4862
Add official pip wheel packaging for `faiss-cpu`, enabling
`pip install faiss-cpu` from PyPI. Builds binary wheels across Linux
x86_64/aarch64, macOS arm64/x86_64, and Windows x86_64 for Python 3.10-3.14.
Linux and macOS use Python Stable ABI (abi3) — a single cp310-abi3 wheel
per platform works on all Python 3.10+ versions without per-version rebuilds.
**BLAS strategy:**
- Linux (x86_64 and aarch64): Threaded OpenBLAS (`libopenblaso`). The
CMake build prefers `libopenblaso` (OpenMP-threaded) or `libopenblasp`
(pthreads-threaded) over the serial default on RHEL/Fedora-based
manylinux containers.
- macOS: Apple Accelerate (found automatically).
- Windows: Prebuilt OpenBLAS from GitHub releases (v0.3.30).
**SIMD optimization strategy:**
- Linux and macOS: Dynamic Dispatch (`FAISS_OPT_LEVEL=dd`) compiles SIMD-hot
kernel files at multiple ISA levels (generic + AVX2 + AVX-512 on x86_64,
NEON + SVE on aarch64) into a single library. Runtime CPUID detection
selects the optimal code path automatically.
- Windows: MSVC does not support DD, so uses `FAISS_OPT_LEVEL=generic`.
Shared libraries (`BUILD_SHARED_LIBS=ON`) are used to avoid MSVC's
single-pass static archive scanning issue.
**New files:**
- `pyproject.toml`: scikit-build-core build backend config with cibuildwheel
settings. Version is dynamically extracted from CMakeLists.txt. Enables
abi3 on Linux/macOS via SWIG 4.2+ and NumPy 2.0+ Limited API support.
Enables LTO and dead-code stripping for smaller wheel sizes.
- `.github/workflows/build-pip.yml`: CI workflow using cibuildwheel to build
binary wheels on 5 platform runners. All GitHub Actions are pinned to
commit SHAs for supply chain security. Publishes wheels to PyPI via OIDC
trusted publishers on tag push.
- `THIRD_PARTY_NOTICES`: License notices for bundled dependencies (OpenBLAS,
LLVM OpenMP).
- `tests/test_wheel_smoke.py`: 12-test smoke suite validating import,
OpenMP, BLAS (FlatL2/FlatIP), index factory (IVF+PQ), HNSW, serialization
roundtrip, GC safety, contrib imports, and SIMD level detection.
**Modified files:**
- `faiss/CMakeLists.txt`: Added threaded OpenBLAS fallback — prefers
`libopenblaso` (OpenMP-threaded) or `libopenblasp` (pthreads-threaded)
over the serial default on RHEL/Fedora-based manylinux containers.
- `python/CMakeLists.txt`: Added `install()` targets for scikit-build-core
wheel packaging, including all Dynamic Dispatch SWIG variants
(avx2/avx512/avx512_spr/sve). Added abi3 support: conditionally uses
`Python::SABIModule`, defines `Py_LIMITED_API`, and sets `.abi3.so` suffix
when `SKBUILD_SABI_VERSION` is set.
- `.github/workflows/build.yml`: Wired `build-pip.yml` into the root CI
trigger so pip builds run alongside conda builds.
- `tests/BUCK`: Added `python_pytest` target for the smoke test.
Reviewed By: mnorris11
Differential Revision: D95258115
fbshipit-source-id: 3593ed4fa5c1d8b7bebfc61c933bb3204c9666eb
